is to visit the ancient Mayan site of Tikal. Tikal is a huge site and in it's heyday would have been home to approx 150,000 people. The unusual thing about this site is that it was built in a place where there is no natural water source. They therefore had to build a complicated canal system to transport rain water from the high areas into a number of huge reservoirs (like this one) which was then distributed through the site by an extensive drainage system.