Apr 1 2016SaveSpace4/1/16Space4/1/16We Finally Know What's Up With These Enormous Mounds on MarsMaddie Stone37SaveFor forty years, astronomers have puzzled over the miles-high mounds rising from of the centers of Martian craters.…
Oct 30 2015Save10/30/15Newly-Discovered Geoglyphs Are So Big, NASA Is Helping Study Them From SpaceKelsey Campbell-Dollaghan52SaveTurgai, Kazakhstan might not look like much besides wide, sweeping plains. But over the past few years,…
Oct 31 2010Save10/31/10Artificial mound protected Britain for thousands of yearsAlasdair Wilkins60SaveSilbury Hill is a huge artificial mound in southern England, about 130 feet high and covering five acres. Europe's…