The ruins of Kharkhorum mark the former Mongol imperial capital just north of Erdene Zuu Monastery. The remains are low and scattered, but the site still gives a useful sense of where the palace area and city enclosure stood.
Look for the fenced excavation areas and the stone turtles that once marked important points in the city. The ruins work best as a companion stop to Erdene Zuu and the Kharakhorum Museum, where the history is easier to piece together.