About 1 hour away from Bogota is the small town of Zipaquira. I took a day trip there using public transportation to come see the famous Cathedral Del Sal. They have many mines in Zipaquira, where they mine the underground salt formed ages ago when the ocean got sunked into the earth by the movement of the earth plates. Prehistoric salt !
I think the church bought one of these mines and built a church within the mine and carved sculptures and statues on the salt blocks. It was an impressive sigh to see these huge salt carvings. The church is a fully functional church and they have mass there every Sunday.
Apart from visiting the church, I also took a mine tour, where they explain how mining works and they brought us in the mines and showed us how the salt mining is actually done. They explained how plates moves and the earth movement and all, and in 300 years, that entire mine/church will be gone, as the walls of the mine keep on decreasing in size.
Also, in the mine, they have the world's largest salt mirror. It's a salt lake which is so dense with salt, that it's exactly like a mirror. It was an amazing view !