Where is the worlds next perfect city?: The experts check in

There are two kinds of people in this world: Those who love Barcelona and those who haven't been there yet.

Barcelona is as close to a perfect city as there is and an obvious destination for most any kind of traveller: warm, sunny, kissed by Mediterranean breezes, full of nice-looking people and quality restaurants, rife with history and beautiful architecture, safe and with plenty of English spoken. Barcelona is about as mainstream and predictable as travel gets in 2015.

But less than 30 years ago, Barcelona might as well have been the South Pole to most travellers. During a recent trip to Spain's second city, I was told again and again that the city got very little tourism before hosting the Summer Olympics in 1992. Since then, tourism has become the city's economic engine.

And that got me wondering what the next Barcelona might be. That is, what cities (or countries or regions) currently hovering under the radar will be mainstream destinations in another 20 to 30 years? I asked some seasoned travellers for the answer.

— Cameron Hewitt, guide book author for "Rick Steves' Europe"

"This is one of my favourite topics, and a lot of those places are in Eastern Europe. Krakow has become popular. Ljubljana, the capital of Slovenia, is a gem; the only reason people aren't flocking to it is a lack of awareness. Sarajevo is an amazing city. But I'll go with Budapest. It's a magnificent city that my European friends, who are ahead of me on this stuff, all love. It's always been a fascinating city, and during the last five or 10 years, it has been cleaned up and become much more inviting. It has some of the best nightlife in Europe with great food and wine culture."

— Katie Aune, travel blogger

"Tbilisi, Georgia, is already on the radar of food and wine aficionados, hosting the International Wine Tourism Conference in 2014, and it won't be long before it goes mainstream. This former Soviet capital features a charming old town, bustling nightlife and centuries-old churches, all sitting in the shadows of the Narikala fortress, now accessible by an aerial tramway. Though a destination in its own right, Tbilisi also provides a great base from which to explore the rest of Georgia, including wineries, ancient monasteries, scenic mountains and beaches along the Black Sea coast."

— Chris Cohen, associate editor, Outside magazine

"Shanghai. It's already a financial powerhouse but never mentioned in the same breath as London, Paris, Tokyo or New York. But as the centre of the world moves east, direct flights become more frequent and faster, and China morphs into a viable destination for casual, short-term travellers, a visit to this megalopolis will become as routine as a visit to those other urban superstars."

— Tom Hall, editorial director, Lonely Planet

"Iceland, I think, is almost there. Halfway between Europe and North America, it boasts strange and unique scenery, great food and drink, wildlife, home comforts, spas and lots more."

— Lee Abbamonte, travel blogger who claims to be the youngest American to visit every country in the world

Any of the Caucasus countries; it's an awesome part of the world to visit, and it's my No. 1 area to go back to. I'd single out Georgia. It has good infrastructure, all levels of hotels and both ruins and modern history. Tbilisi is one of the coolest cities no one has been to. There's a lot of culture to absorb, and the food is phenomenal."

Julia Cosgrove, editor-in-chief, Afar magazine

"Portugal has something to prove to the world next year: It's done being overshadowed by its neighbours. There's a great up-and-coming food scene in Lisbon, between restaurants and the recently renovated Time Out Mercado da Riberia, where travellers can discover Lisbon's best artisanal food purveyors. In terms of infrastructure development geared to travellers, there's a new cruise terminal opening in the city next year, as well. You heard it here first: Lisbon is the new Barcelona."

A new Barcelona? Lisbon, here we come!

TNS