It's something we don't always think about, but where and how we travel can have a big impact on the places we visit, particularly now that more than a billion of us travel internationally each year. "Every time we travel," says UN World Tourism Organisation (UNWTO) secretary-general Taleb Rifai, "we become part of a global movement that has the power to drive positive change for our planet and for all people."
With tourism now the world's largest industry – accounting for 260 million jobs and almost 10 per cent of global GDP –spending our disposable income in foreign lands helps in all sorts of ways, from stimulating economies and promoting employment and education to giving economic value to natural resources that might otherwise be exploited out of existence.
Tourists wanting to see orang-utans in Borneo, for example, are pressing "pause" on a palm oil industry destroying their forest habitats. Travelling in developing countries has kickbacks for us too, of course: affordable holidays and firsthand experiences that open our minds and hearts to the world. In fact the more we travel, the more aware we become of world affairs and the more we care about people whose lives may be affected by them, all of which makes us more likely to give back on our next trip. So where should we go to do the most good? One clue lies in this paradox: countries most dependent on tourism suffer twice when natural disasters or other events turn off the flow of visitors – but are quick to recover when travellers return.
In other words, the places we love to visit on holiday are the ones we rush to help when they're in trouble. Think Bali after the 2002 bombing; Sri Lanka, Indonesia and Thailand after the Boxing Day tsunami; Christchurch and northern Japan after the 2011 earthquakes and tsunami; and, more recently, Nepal after massive earthquakes earlier this year and even Paris following the recent terror attacks which has seen mass cancellations of hotel and tour bookings.
Tourism in the world's favourite trekking destination ground to a halt after the April-May earthquakes that killed 9000 people and left hundreds of thousands homeless. But with hotels and major trails in Nepal open again, just in time for the post-monsoon October-May trekking season, now is the time to go.
"Trekking is a great way to inject tourism dollars into the most marginalised communities," says Sue Badyari, chief executive of World Expeditions, based in Sydney, "because every trekking group employs up to 25 local people from remote mountain areas, from porters and kitchen staff to cooks and trek leaders."
World Expeditions has six new Rebuild Nepal Treks that include five-10 days of hands-on work repairing schools in some of the hardest-hit areas, funded by the World Expeditions Foundation, and is running treks for outdoor equipment brands Paddy Pallin and Kathmandu.
Melbourne-based Intrepid Travel, the largest trekking operator in Nepal, is taking a different tack, donating all profits from its 2015-16 season to charities working in Nepal, with a goal of raising $1 million by June 2016. Either way, "every traveller, every trekker, every person who visits Nepal this year will be directly contributing to the rebuilding effort", says James Thornton, Intrepid's managing director.
Two other countries in our region needing tourism after natural disasters are Vanuatu, which was hit by category five cyclone Pam in March and launched a #YourHolidayHelps campaign in May urging people to book trips and share their holiday snaps on social media; and Sabah in Malaysian Borneo where Mount Kinabalu, one of the country's main drawcards, has just reopened after a magnitude 6.0 earthquake killed 18 trekkers in June. (A new track to the summit will open in December.)
Then there are countries in conflict, or perceived to be. "Syria will be written off for tourism for a long time now. We stopped running trips there two years ago because of the civil war," says Geoff Manchester, co-founder of Intrepid Travel. "But Jordan has also suffered because of its proximity to Syria. We used to take people from Cairo to Istanbul a couple of times a week, in both directions. That has totally stopped now."
To entice travellers back, hotels and tour operators in Jordan have been cutting their rates and the Ministry of Tourism recently launched the Jordan Pass, which gives visitors discounted tourist visas and free entry to sites such as the World Heritage-listed city of Petra, where visitor numbers have halved since 2010.
Travel has also slowed to a trickle in Egypt, since the 2011 revolution. "Five years ago, Egypt was one of the biggest destinations in the world," says Manchester. "We've started to see signs of tourism recovery this year, but we're still a long way from pre-revolution levels of travellers. It needs to not be in the news for six-12 months, to restore travellers' confidence."
On the upside, visit Egypt soon and you'll have it pretty much to yourself. When travel writer Belinda Jackson was in Cairo recently, she found the lack of foreigners "almost eerie: the pyramids are deserted, as is the Egyptian Museum, though the country is undergoing a massive infrastructure boost".
"For photographers, it's a great opportunity to get that perfect landscape shot without a hundred Spanish coach tourists in it."
A side effect of the Arab Spring and subsequent unrest in the Middle East has been "a disturbing anti-Muslim sentiment creeping into travel, a resistance to visiting Islamic countries", says Badyari. "Hopefully it will pass, because we need to visit such places precisely to remind ourselves that the majority of people, all over the world, are friendly and want to live in peace."
One London-based tour operator is doing its best to counteract traveller resistance to certain destinations, in the name of adventure. Run by ex-British Army officers, Secret Compass ran its first trip in 2011, to eastern Afghanistan (sensibly side-stepping Kabul).
The following year it was the first commercial operator to go to South Sudan, the world's newest country, and its 2016 trip list reads like a roll call of no-go zones, including a high-altitude winter trek in Iraq and a jungle expedition in Panama's infamous Darien Gap.
"Visiting places like Afghanistan, Sinai, Iran and Iraqi Kurdistan is vital on so many fronts," says Secret Compass chief executive and co-founder Tom Bodkin. "The fact that our teams even go to these places sends positive messages to the locals in countries avoided by travellers due to generalised or outdated reporting.
"Our adventures foster optimism, as local people realise that the outside world perceives their country as a safe and welcoming place to visit once more. Our presence helps to stimulate fledging tourism economies.
"And through the post-travel reports of our team members [Secret Compass clients] – their conversations, Facebook photos and blogs, for example – the good news ripples out, so increasing numbers of people realise that certain destinations really are OK to visit again. As long as it's managed carefully, adventure travel in regions such as these can be a win-win situation."
Of course, you can wait for conflict and civil strife to pass before returning to troubled destinations and that's often when they need us most. The north-east of Sri Lanka is accessible again after more than 25 years of civil war; Intrepid Travel will run trips to Jaffna and the untouched beaches around Trincomalee from July next year.
New trips to North Korea are capitalising on traveller curiosity about this long-closed, and in some ways, much misunderstood country. It can take time for countries to recover, of course. Kashmir, in northern India, re-opened to tourists two years ago when the Department of Foreign Affairs and Trade (DFAT) relaxed its advice, and is "cautiously marching ahead", says Badyari. "People can now enjoy this part of India again, have a houseboat experience, visit historic Moghul gardens. It was once a great Himalayan destination and it will be again, thanks to tourism."
Myanmar too, where opposition leader Aung San Suu Kyi's National League for Democracy won by a landslide at an historic general election earlier this month, is still "crying out for more travellers," says Brett Tollman, chief executive of The Travel Corporation and its not-for-profit TreadRight Foundation. "Not just for economic reasons, but to learn about and meet the people there, who also gain from meeting us, people from outside their country."
Re-opening to visitors can also bring greater transparency that can benefit a country's citizens, says Manchester. "We all know about Tiananmen Square in 1989, but most of us don't know about the pro-democracy demonstrations started by students in Yangon (Myanmar's capital) in 1988, which led to a military coup during which thousands of civilians were killed.
"Wherever there are tourists, governments think twice about how they treat their people, because tourists are increasingly bearing witness to world events and recording and sharing what they see."
Sometimes it's unclear whether visiting a country is the best way to help. Until recently, Greece needed tourists and their euros to assuage its economic woes, and travellers obliged despite warnings about potential inconveniences such as ATMs running out of cash.
Now the escalating refugee crisis – more than half a million refugees have arrived in Greece this year from Syria and other affected countries – makes that less clear. In fact the whole of Europe is in limbo.
At the time of writing, Sweden has just introduced border checks to process the 10,000 asylum-seekers it receives each week, other European countries are rethinking the entire Schengen Area open-border policy and Paris, one of the world's most visited cities, is reeling from its second terrorist attack this year.
Terrorism has contradictory effects on tourism, it seems, opening our hearts to the destinations affected while also making us wary. Another factor at work here is that we tend to see terrorist attacks as isolated events in Western countries but as part of a systemic problem in more exotic places, says Manchester.
"Tourists tend to return quickly to cities like New York and London partly because they're more relatable places, partly because of how the events are covered by media. While there may be a drop in visitor numbers to Paris, we'd expect it to bounce back more quickly after the latest attack [on November 13] than in places like Tunisia or Kenya."
Africa needs visitors like never before, having experienced its greatest decline in tourism in living memory after the outbreak of Ebola last year – although some commentators have called it an "epidemic of ignorance" because fear of the virus, which has affected only three West African nations (Sierra Leone, Liberia and Guinea), has spread to the entire continent.
"The risk was as low as travelling in Asia or Europe, but some people didn't see it that way," says Badyari, whose company, World Expeditions launched a campaign late last year to reassure travellers and remind them of the humanitarian impact of cancelling their trips.
Adding to the confusion is the fact that the Australian Government's Department of Foreign Affairs (DFAT) currently has "do not travel" alerts for nine African countries including Somalia, Burundi and Niger because of armed conflict or the risk of kidnapping. But that doesn't mean it's not safe to travel to Kenya, Tanzania, Morocco, Namibia, South Africa – or Ethiopia.
"People hear the word Ethiopia and think: drought, famine, desert," says Bodkin, whose Secret Compass runs mountain biking trips in the Simien Mountains. "They're stuck in the '80s and the era of Geldof's Live Aid … [but] adventure tourism is really picking up for the region, which is great for small-scale operators and makes now a great time to go."
Another way to have a positive impact on Africa, and other destinations, is by going to see its wildlife, preferably in the wild or in sanctuaries that recreate wild conditions as much as possible, says Nicola Beynon of World Animal Protection, which helps by "funding conservation, deterring poaching and creating advocates for protecting biodiversity and the world's natural environments".
In a nod to the growing importance of animal-friendly tourism, World Expeditions, in partnership with World Animal Protection, last month launched its Animal Welfare in Tourism Code of Conduct, an industry first.
Where to go, to help the world's wild animals? Whale-watching in Iceland or Norway helps eco-tourism become more profitable than whaling. You could take a safari in east Africa, particularly in Tanzania or Mozambique, both of which have lost more than half their wild elephants to poaching in the past five years; or South Africa, where rhino poaching is at record levels.
The mountain gorillas in Rwanda and Uganda need us, as do the orang-utans in northern Sumatra, the tigers in India and snow leopards in Bhutan and Ladakh, in northern India.
Whether we're visiting countries after natural disasters or terrorist attacks, offering hands-on help or seeking a new take on misunderstood cultures and creatures, travel that benefits and respects the people and places we visit is a powerful force, one we can all participate in for a better world.
ECO-LUXURY, FRENCH POLYNESIA The vision of Hollywood eco-warrior Marlon Brando, who died before it opened in July 2014, The Brando is a 35-villa luxury eco-resort on a private island that uses solar energy, a coconut oil-fuelled generator and a pioneering deep seawater air-conditioning system. Villas from $3650 a night. See thebrando.com
INTO NORTH KOREA World Expeditions and Intrepid Travel both have new tours to the People's Republic in April 2016: an eight-day sightseeing adventure called the North Korean Explorer (costs $3690, see worldexpeditions.com) and a Pyongyang Marathon trip for runners and non-runners (the nine-day trip costs $3295, see intrepidtravel.com).
HORSES IN THE HOLY LAND This 15-day horse-trek to Israel and the Occupied Palestinian Territories in April 2016 (cost $6300) retraces Mark Twain's trip in 1867, and includes meeting Israelis, Jewish settlers, Bedouins and Christian and Muslim Arabs, and sleeping in kibbutzim and desert camps. See secretcompass.com
TREK THAILAND FOR A CAUSE Help end the dog meat trade by trekking in northern Thailand for four days, then spending two days helping at Soi Dog Foundation shelter in Phuket, in November 2016. The 11-day trip costs $4390 plus a fund-raised donation. See inspiredadventures.com.au
HOME-GROWN MYANMAR Trafalgar's 11-day Secrets of Myanmar trips ($4550) start in January 2016 and include sightseeing in Yangon, Bagan, Mandalay and Inle Lake and exclusive interactions with local people through cooking classes, monastery visits and other experiences. See trafalgar.com
Intrepid Travel stopped offering elephant rides – which are "inherently cruel", says World Animal Protection – last year and more than 80 operators worldwide have pledged to do the same. Do: visit elephant orphanages and sanctuaries for rescued or abused elephants. See worldanimalprotection.org.au; elephantnaturepark.org
If you've seen the films The Cove or Blackfish, you'll know why you shouldn't swim with captive dolphins or visit aquariums that feature performing dolphins or orcas. Marine mammals belong in the ocean and suffer enormously in captivity. Do: swim with dolphins and other marine mammals in the wild, on their terms. See dolphinproject.net; dolphinencounter.co.nz
Orphanages can do more harm than good, tearing families apart and forcing children to live in substandard conditions, and visits rarely help. Do: support organisations that keep families together or sponsor a child. See thinkchildsafe.org, scv.org.au (Australian-run Sunrise Children's Villages).
Don't buy souvenirs or any products that include ivory, fur, feathers, shells or coral or Chinese medicines made from endangered or threatened species. Do buy souvenirs that are hand-made from local, recycled or renewable materials. See checklist.cites.org
Children on the streets are vulnerable to abuse and exploitation, and child trafficking is a worldwide issue. Do donate to local charities or schools, or take a tour that benefits an entire community. See childsafetourism.org; kiberatours.com
There are some precautions you can take as a measure against unforseen events and for some peace of mind, wherever you're headed.
Register your travel plans with Smartraveller, the travel advisory run by the Australian Department of Foreign Affairs and Trade, even if you're travelling on a group tour or a cruise, so DFAT can contact you or notify your family in an emergency. You can also subscribe to updates on its travel advice for countries or regions you plan to visit. See smartraveller.gov.au
Check your travel insurance. Most travel insurers cover you against unexpected events such as terrorist attacks, riots and natural disasters, as long as you don't put yourself in harm's way and you're not in a country that already has a current DFAT "Do not travel" alert. Some insurers, such as Allianz Group, have their own travel advisories but still use the advice issued by the Australian government to evaluate claims.
Use Facebook Safety Check – when it is activated. Safety Check was created last year to allow Facebook users to let their friends and family know they're safe when natural disasters hit, such as the earthquakes in Nepal. That changed during the Paris attacks, when 4 million people in the city ticked "I'm safe" within 24 hours; Facebook has said it will now activate it during selected "human disasters" too. See facebook.com/about/safetycheck/.
See also: Why you should visit the good places where bad things happen
Sydneys The Goods Line and seven other high lines around the world
Nashville’s Civil War sights: finding Music City’s dissonant sounds
Lyon: Frances little piece of Italy
Best things to do in Brisbane in winter 
Political tours: A trip to Israel and Palestine
In the shadow of Mt Fuji: great trips from Tokyo
