Museo Nazionale di Castel Sant'Angelo, Rome

Great old castle, nice placement near the Tiber river. The view is gorgeous, especially at sunset since the Basilica of St. Peter can be seen in the background. Also, the pedestrian bridge over the river is a romantic place with people that play slow songs on the guitar. We did not enter because the castle was closed, but it was pretty crowded so I suppose you should get tickets in advance if you want to visit the inside.

A beautiful castle. The experience is straight forward, but you can easily spend at least 1.5 hours here excluding the garden. There is a floor with an exhibition room, then several paths deeper and upper into the castle, but still straight-forward enough to see everything. You will see fortress interior areas, castle walls, exhibits of old weaponry and paintings, and of course many grand rooms with beautiful art covering the ceiling and walls. Tickets 14€~