The headline sight is — or was, and will be again — Wangdue Phodrang Dzong, the rambling 17th-century fortress that sits on the ridge above the river junction. A devastating 2012 fire reduced most of the dzong to ashes; the painstaking reconstruction has been under way ever since, and visitors can usually see the works from outside.
A short detour off the main east-west highway takes you to the Phobjikha Valley, the broad glacial valley to the south where black-necked cranes spend the winter. Many travellers detour from Wangdue specifically for this — it is the single best wildlife experience in western Bhutan.