Veliko Tarnovo is a city in north central Bulgaria and the administrative centre of Veliko Tarnovo Province. Often referred to as the "City of the Tsars", Veliko Tarnovo is located on the Yantra River and is famously known as the historical capital of the Second Bulgarian Empire, attracting many tourists with its unique architecture. The old part of the city is situated on the three hills Tsarevets, Trapezitsa, and Sveta Gora, rising amidst the meanders of the Yantra. On Tsarevets are the palaces of the Bulgarian emperors and the Patriarchate, the Patriarchal Cathedral, and also a number of administrative and residential edifices surrounded by thick walls. Trapezitsa is known for its many churches and as the former main residence of the nobility. During the Middle Ages, the city was among the main European centres of culture and gave its name to the architecture of the Tarnovo Artistic School, painting of the Tarnovo Artistic School, and to literature. Veliko Tarnovo is an important administrative, economic, educational, and cultural centre of Northern Bulgaria.