There were originally several churches in the Nizhny Novgorod Kremlin, but today only Michael the Archangel Cathedral exists. It was built in the middle of the 16th century and rebuilt in 1628-1631. The cathedral is the tomb of Kuzma Minin. In 1828, in front of the Archangel Cathedral was constructed the obelisk in honor of Kuzma Minin and Dmitry Pozharsky (by architects Melnikov and Martos).
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.