Bulgaria is a country in Southeast Europe. It is situated on the eastern flank of the Balkans. Bulgaria covers a territory of 110,994 square kilometres (42,855 sq mi), and is the sixteenth-largest country in Europe. It had a population of 6,520,314 in 2021. Sofia is the nation's capital and largest city; other major cities are Plovdiv, Varna and Burgas.

The Belogradchik Fortress, also known as Kaleto, is a historical landmark located in the town of Belogradchik, Bulgaria. It is a medieval fortress situated on the slopes of the Balkan Mountains and is known for its unique rock formations and stunning natural scenery.

Tsarevets Fortress is a medieval stronghold located on a hill with the same name in Veliko Tarnovo, the former capital of the Second Bulgarian Empire. The fortress is a significant historical and architectural monument, and it played a crucial role in the medieval history of Bulgaria.

The Old Town of Plovdiv, located in the city of Plovdiv, Bulgaria, is a historical and architectural gem that reflects the rich cultural heritage of the region. Plovdiv is one of the oldest continuously inhabited cities in Europe, with a history dating back thousands of years.

The ancient theater of Philippopolis was built during the time of the Roman emperor Marcus Ulpius Trajan (98 – 117 AD). and was discovered during archaeological excavations from 1968 to 1979 by the Plovdiv Archaeological Museum. It is located between Jambaz Tepe and Taksim Tepe.