Metropolitan Cathedral of Rio de Janeiro,

Resembling a huge, futuristic Mayan pyramid, it is impossible not to be amazed by this architectural downtown wonder. Officially opened in 1976, while still incomplete, it has a capacity of over 20,000 people. The interior is a virtual cavern, with an open space 300 feet high, no supporting columns and a granite rock that forms the altar. No matter what you think about its unusual exterior beehive shape, the four huge stained glass windows will grab you. The underground part of the cathedral houses the Sacred Arts Museum.