The black waterfall “Svartifoss”. It formed by cooling of Lava in Aerial condition (cooling in the air) that cause the recent structure look likes a long column called “Columnar Basalt” via Tumblr http://bit.ly/1O0EbsL
STEM Enthusiast, Learner, Informatics Analyser, Foodie, Photography, CAD Designer, AI Snooper, Doing MBBS.