Mud volcanoes. It's estimated that 300 of the planet's estimated 700 mud volcanoes sit Gobustan, Azerbaijan and the Caspian Sea. Many geologists as well as locals and international mud tourists trek to such places as the Firuz Crater, Gobustan, Salyan and end up happily covered in mud which is thought to have medicinal qualities. In 2001 one mud volcano 15 kilometers from Baku made world headlines when it suddenly started spewing flames 15 meters high. uit: www.travelblog.org/Asia/Azerbaijan/blog-149231.html