Construction of the Cologne Cathedral began in the 13th century and spanned centuries, with its completion in the 19th century. It is a prime example of High Gothic architecture, boasting intricate detailing, soaring spires, and an elaborate façade adorned with countless statues and decorative elements. The cathedral's most iconic feature is its twin spires, which rise to an impressive height and dominate the city's skyline. The interior of the cathedral is equally awe-inspiring, with stunning stained glass windows, ornate chapels, and a magnificent altar. As a place of worship, the Cologne Cathedral serves as the seat of the Archbishop of Cologne and remains an active religious center. It also holds cultural significance, housing a rich collection of religious relics and artifacts.

The Alter Markt has a rich history dating back centuries, and it was once the site of medieval markets, fairs, and public gatherings. Today, it continues to be a hub of activity, but it also serves as a picturesque destination for both residents and tourists. One of the most iconic landmarks on the square is the Cologne City Hall, or "Kölner Rathaus," a stunning Gothic-style building that dominates the square's eastern side. The City Hall is known for its intricate architecture, including the ornate loggia and the picturesque tower.

Built during the Roman period around the 2nd century AD, the Römerturm was originally part of the Roman city walls that surrounded the ancient settlement of Colonia Claudia Ara Agrippinensium, which later became Cologne. The tower served as a watchtower and was an integral part of the city's defenses. Today, the Römerturm stands as one of the few remaining remnants of Roman Cologne, making it a precious historical landmark. It is particularly notable for its cylindrical shape and the use of Roman bricks in its construction.

Constructed in the 13th century, the Hahnentor was one of the original gates in Cologne's medieval city walls. Its distinctive name, which means "Rooster Gate" in English, is derived from the decorative weather vane featuring a rooster perched atop the gate. The gate served as a passage for travelers entering the city and played a vital role in Cologne's defenses during its medieval period. Over the centuries, it witnessed significant historical events and was an integral part of the city's life. Today, the Hahnentor stands as a well-preserved testament to Cologne's medieval past and the importance of its city gates.