Lan Xang was at the center of the overland trade routes in Southeast Asia. In the north and northwest the overland trade routes from Burma and Lanna passed through Lan Xang and Sipsong Panna ( Xishuangbanna ) toward Yunnan, where they would join with the Chinese Tea-Horse Road. Trade in Luang Prabang would flow down the Mekong to Vientiane where it could then be transported overland to the headwaters of the Nan and Chao Praya rivers, or overland by ox cart or elephant over the Khorat Plateau to Roi Et.