Cuevas del Drach are caves located next to city of Porto Cristo in Mallorca. It contains one of the largest underground lakes in the world. When we were there, they were showing documentary about Jules Verne and the Journey to the center of the Earth on the cave walls. Together with the music and echoes, it was really cool experience. Once you reach the underground lake (Lake Martel), you can see musicians on the boat playing classical music.
Salar de Uyuni, Bolivia These 4,086 square miles in southwest Bolivia make up the world’s largest salt flat. The vast and incredibly flat plains and clear skies of Salar de Uyuni make it both one of the most famous “natural mirrors” on the planet, as well as an ideal altimeter calibration site for Earth observation satellites. 31 of 75 of the most colorful places in the world to go to.