The Church of St. Michael in Synkavichy is a Gothic church was built in 16th century. It is one of the first fortified churches in Grand Duchy of Lithuania. In 1880-1881, the temple was significantly reconstructed. In 1926, it was rebuilt as a Catholic church. In 1988-1990, it become Orthodox. This site was added to the UNESCO World Heritage Tentative List in 2004.
The defensive system of the church consists of four towers and loopholes placed under the vaults. The interior of the church looks like a hall, its cross-shaped vaults with nervuses rest on six pillars. With the purpose to improve the defence capacity the windows are raised high above the ground.
References:The Walls of Constantinople are a series of defensive stone walls that have surrounded and protected the city of Constantinople (today Istanbul) since its founding as the new capital of the Roman Empire by Constantine the Great. With numerous additions and modifications during their history, they were the last great fortification system of antiquity, and one of the most complex and elaborate systems ever built. They were also the largest and strongest fortification in both the ancient and medieval world.
Initially built by Constantine the Great, the walls surrounded the new city on all sides, protecting it against attack from both sea and land. As the city grew, the famous double line of the Theodosian Walls was built in the 5th century. Although the other sections of the walls were less elaborate, they were, when well-manned, almost impregnable for any medieval besieger.