Muaro Jambi is the great reason to come to Jambi. The temple compounds spread across a broad area near the Batanghari River, with brick ruins, restored shrines, ponds, and village paths tied to the old Malayu and Srivijaya worlds.
The scale is the surprise. This is not one temple beside a car park, but a landscape you move through, ideally by bicycle or with a local guide. Go early, take water, and allow time for the small site museum as well as the main temple clusters.