Housed in the grand neoclassical former Post Office on Calea Victoriei, this museum holds Romania's national treasure: the Pietroasele gold hoard, the Cucuteni-era pottery, the medieval royal regalia, and one of only two full-scale plaster casts of Trajan's Column anywhere in the world (the other is in Rome). The cast is in 125 sections you can walk around at eye level, which is the best way to study the famous frieze.
Much of the building is closed for long-running restoration but the Treasury and the Lapidarium, where the cast lives, remain open and are the parts most worth seeing. Entry is cheap and the museum is rarely crowded. Allow about 90 minutes for the Treasury alone.