 They include curvilinear shapes like spirals and concentric circles, tree-like shapes, and the distinctive "enveloped cross" motif.The Pohnpaid petroglyphs are the largest assemblage of rock engravings in the region, with motifs dominated by footprints, enveloped crosses, and outlined "sword-paddles".Central Micronesia also hosts the ruins of the stone cities of Nan Madol (1,180–1,200 CE) and Leluh (1,200–1,800 CE), in the islands of Pohnpei and Kosrae, respectively.