#2: Salt Cathedral of Zipaquira, Colombia
Inside the Salt Cathedral of Zipaquira, located about 30 miles north of the Colombian capital Bogota, tourists can view a Catholic church made entirely of salt, with 14 small chapels that represent the stations of the cross. (Luis Acosta/AFP/Getty Images)
As many as 3,000 worshippers make a pilgrimage some 600 feet underground every Sunday for services at the "Salt Cathedral of Zipaquira," located near the town of the same name in central Colombia. Now a popular tourist attraction, the mine is part of a museum complex known as "Salt Park," which tells the story of mining and geology here in this south American nation.
Zipaquira's history as a place of religious worship dates back to the 1930s, when miners set up a makeshift altar as a place for daily prayer before work. The salt deposits here are believed to date back much further than that – as long ago as 250 million years.