Outstanding examples of medieval religious architecture in the Caucasus are the historic churches of Mtskheta, the former capital of Georgia. They are a testament to the high level of artistic and cultural achievement of this ancient kingdom. Because of the historical importance of the city and its many exceptional churches and cultural monuments, the "Historical Monuments of Mtskheta" became a UNESCO World Heritage Site in 1994. As the cradle and one of the liveliest centers of Christianity in Georgia, Mtskheta was designated a "Holy City" in 2014 by the Georgian Orthodox Church. The Mtskheta Historic Sites are situated in the cultural region at the junction of the Aragvi and Mtkvari Rivers in Central-Eastern Georgia, approximately 20 km northwest of Tbilisi in Mtskheta. The complex includes Jvari Monastery, Svetitstkhoveli Cathedral and Samtavro Monastery. Mtskheta was the ancient principal city of Kartli, the Kingdom of Iberia, in Eastern Georgia between the 3rd century B.C. and the 5th century A.D. Chronicles mention, but some historians do not accept, that the kingdom of Iberia and its capital were taken by Alexander the Great in the 4th century BC. Finally, the ruler chosen by Alexander destroyed the walls of Mtskheta, leaving only four fortresses, one of which is known today as Armazi. Mtskheta was also the place where Christianity was declared the official religion of Georgia in 337. At that time, the city of Mtskheta was a culturally developed city. Today, the city remains the seat of the Georgian Orthodox and Apostolic Church.