More than 2,000 large ancient stone jars are spread across a plateau in the Xiengkhouang province of cen­tral Laos. Some stand 10 feet tall and weigh sev­er­al tons. Archae­ol­o­gists esti­mate the jars are 2,000 years old, but their pur­pose is unclear. The most com­mon the­o­ries are that they were used as funer­al urns.