Another one of the city's many religious structures, the Saint Nedelja Church dates back to as early as the 16th century, and can be found in the heart of Sofia. If you enjoy old icons and beautiful architecture, stop by along the route of your itinerary.

The domed Gare des Bénédictins, the city's train station with its 60 meter tall clock tower is surely one of the world’s most beautiful train stations and surprisingly Limoges' top sight. You don't need to be embarking on a train, but this is a must-see in Limoges.

Built under Emperor Vespasian in A.D. 70-72 and completed by his son Titus 10 years later, the Flavian Amphitheatre, or the Colosseum, is a massive stone arena, which at its peak, could accommodate 80,000 spectators. As in the movie 'Gladiator,' the Colosseum has hosted violent and brutal displays of gladiatorial combats and wild animal fights, all just for the delight of crowds. The inauguration lasted one hundred days, and approximately 9,000 animals and 2,000 gladiators were killed during the event. Today, the Colosseum is Rome's most visited sight, which never fails to leave visitors awe-struck. Be sure to also come here at night when it looks even more magical.

In the year 64 AD, Emperor Nero built a palace almost one mile long — stretching from Palatine Hill all the way to Oppio Hill. Some parts were covered in gold, precious stones and featured splendid decor. After Nero’s death, it was filled in with earth to obliterate the tyrant’s memory. It was accidentally rediscovered in the 15th century, and today, you can walk through 30 of Nero’s 150 underground rooms.