Dahshur

Think of Dahshur as pyramid-proving grounds: Although not nearly as famous at the pyramids of Giza, the structures here pre-date the Great Pyramids and highlight the engineering progress and understanding that took place on the way from a stepped structure to a true pyramid. The royal necropolis at Dahshur comprises a two-mile (3.5-kilometer) field of pyramids that date back between the fourth and 12th dynasties, and although 11 structures once dotted the landscape, only two remain: the Red Pyramid and the Bent Pyramid. Nearly identical in size, these two pyramids are the third-largest in the country after the two biggest at Giza. The Red Pyramid is the older of the two and the only one that visitors can actually enter.
Archaeologists believe that Snofru, the first Pharoah of the fourth dynasty, commissioned Dahshur's most notable pyramids, and, as the Bent Pyramid with its crooked peak illustrates, not all takes were entirely successful. It towers above the sand not far from the Nile's fertile green band and is believed to have been the first try at a smooth-sided true pyramid. 
It’s said thousands of people spent decades building the ultimately-flawed Bent Pyramid before trying again just over a mile to the north with the Red Pyramid, incorporating some lessons learned and a different type of stone, which shines red after the rains. Some Egyptologists think the Red Pyramid is where Sneferu was buried.

Practical Info

Dahshur is located 22 miles (35 kilometers) south of Cairo. Visitors hoping for pyramid photos free of tourist throngs and camel touts should consider a visit to Dahshur instead of Giza. Regular private and group tours from Cairo incorporate Dahshur with additional stops to visit the pyramids of Sakarra, Memphis City and sometimes Giza as well. It is possible to take in all of these sites in a half-day, but at least a full day tour is recommended if you plan to enjoy multiple sites. Entrance fees to Dahshur are around L$40 ($5 USD) and are often included in the price of package tours.