Estonia: Kuressaare Citadel on Saaremaa Island
Aside from the fact that it’s impossible to pronounce, this was the most beautiful and magnificent castle/citadel in the entire Baltics. And UNESCO doesn’t even know it yet! The citadel was built in 1381 and took 40 years to built. It’s a massive sharp-edges pentagon with moat and bridges and spiky corners and thick wall all surrounding a huge fortress building inside. It’s spextCular at both sunrise and sunset (I went twice). The castle was built by the Livonian Order/Swedish Knights.