Explore the ancient caves of Hang Son Doong, Vietnam. Hang Son Doong is one of the largest caves in the world and features a fast-flowing underground river. For spelunkers, exploring Hang Son Doong is the equivalent of scaling Mount Everest.
Tunnel of Love, Ukraine This tunnel is actually still used today — trains chug through it three times a day to deliver wood to a factory. It's believed that if couples who are truly in love hold hands and cross the tunnel, their wishes will come true.
Philadelphia's Magic Gardens: The Philadelphia’s Magic Gardens is a gallery space and a folk art environment that operates as a nonprofit organization. It is considered to be the biggest work of the mosaic artist, Isaiah Zagar. The Philadelphia’s Magic
Crystal Caves in Mexico. This cave features some of the largest selenite crystals in the world. If you do plan to visit, note that the temperature in these caves often gets up to with percent humidity.