The Berca Mud Volcanoes is a geological and botanical reservation located in Buzău County in Romania. The mud volcanoes create a strange selenar landscape, due to the absence of vegetation around the cones. Its most spectacular feature is the mud volcanoes, small volcano-shaped structures typically a few meters high caused by the eruption of mud and natural gases. Gas analysis shows that the composition varies from site to site, but is mainly methane, with 10-25% Helium, and 2-15% nitrogen.