2. Maly Semyachik Volcano

This stunning compound stratovolcano is a natural wonder located on the Kamchatka peninsula, and features a brilliant green-blue lake. Minerals are believed to be responsible for the color of this hot, acidic lake. Located within the active Troitsky crater, you can join other intrepid hikers in climbing up to get a look at the 600 meter wide formation, or take one of the various tours that are offered instead.