With up to six million visitors a year, this imposing Gothic cathedral by the River Rhine breaks all visitors' records. The Shrine of the Three Kings, said to contain the bones of the wise men who came to baby Jesus, is one of its cherished reliquiaries. The sacred building towering at 157 meters had already started drawing in hundreds of thousands of pilgrims long before it was completed in 1880.

Every year on December 31st, about one million people gather around this classicistic structure dating back to the 18th century to ring in the new year together. And for Berlin's 12 million annual visitors the Brandenburg Gate is always a must-see sight. At one time, the 26-meter-high monument was regarded as a symbol of Germany's division. Now it proudly stands for its unity.

Around 2.4 million tourists come to take a closer look at Germany's parliamentary building each year. During the day, the glass dome on top - desigend by British star architect Sir Norman Foster - sparkles beneath the sky. At night, it shines up into it.

This baroque-style Lutheran church attracts about two million visitors a year. The edifice was destroyed in the 1945 bombing of Dresden near the end of World War II, remaining as a heap of rubble on the city's Neumarkt square. It was rebuilt from 1994 to 2005 after Germany's reunification as a symbol of peace, featuring magnificent paintings inside the cupola and a great deal of gold detail.

This fairytale castle built by Bavaria's "mad king" Ludwig II continues to fascinate people the world over. With its towers, ramparts and magnificent halls, it was conceived by the reclusive monarch as an idealized retreat based on images of medieval castles. In 2015, some 1.52 million visitors came to see Neuschwanstein.

Often said to be the world's most famous ruin, Heidelberg Castle draws about one million tourists annually, many of whom are Americans and Japanese. In the 16th and 17th centuries, the original medieval fortress was expanded to become a splendid palace for the regional Palatine Elector monarch. The edifice was destroyed by French troops in 1689.

The Wartburg castle has a played a key role in German culture and history: Saint Elizabeth of Hungary lived here in the 13th century, dedicating her life to serving the sick and the poor. Over 200 years later, church reformer Martin Luther sought refuge here. Around 35,000 visitors per year admire its art treasures on Display, spanning across eight centuries. (depicted here: Elizabeth's chambers)

In the 18th century, Prussian king Frederick II had his relatively modest summer residence built atop his terraced vineyards in Potsdam just outside Berlin. The single-storey palace survived World War II unscathed. Now, some 350,000 visitors a year admire the preserved interiors presented in their original condition, and wander around the idyllic grounds.