Cave of El Castillo, Spain Some of the oldest known paintings in the world are in the Cave of the Castle, in Cantabria in the north of Spain. Thought to be more than 40,000 years old, many of the ...

Built some 4,500 years ago, they contain tombs and chambers that once held the remains of early Egyptian pharaohs. But modern technology has revealed that the pyramids also contain hidden voids.

General admission tickets cost 550 Egyptian pounds (about $11) per person; kids 5 and younger visit for free. All tickets include access to most of the Egyptian Museum's exhibits, plus restrooms ...