Łuck, Ukraine

The Lubart Castle in Łuck was built in the mid-14th century as the fortified seat of  Gediminas' son Liubartas.
The current castle, towering over the Styr River, was built mostly in the 1340s, although some parts of the earlier walls were used. It repelled sieges by numerous potentates, including Casimir the Great (1349), Jogaila (1431), and Sigismund Kestutaitis(1436). It was there that the Łuck Conference of 1429 took place, attended by Emperior Sigismund,  Vasyl II, Jogaila, Vytautas The Great, and the voivode of Wallachia.
Based on Wikipedia-15.08.2011

A card from Aleksey.