Unique in Greece, the Rotunda is a cylindrical building from the early 4th century AD. The mosaics inside are really impressive. The Rotunda is a massive circular structure, built in 306 AD, with a masonry core. Through its long history, it has gone through multiple periods of use and modification as a polytheist temple, a Christian basilica, a Muslim mosque, and a Christian church once again. A minaret is preserved from its use as a mosque, and ancient remains are exposed on its southern side. Some Greek publications claim it is the oldest Christian church in the world. These days, the Rotunda is primarily an archaeological site, where you can see some remaining Christian mosaics and feel the weight of history.

The narrow pavements and neoclassical buildings of Ladadika host plenty of bars, restaurants, cafes and cute boutiques. The area from Salaminos street to YMCA Park is known as Ladadika Quarter. This is an old quarter that starts at the waterfront and goes a few blocks inland up to Tsimiski Avenue that is busy with international and local brand shops. The northwestern part of the area, closer to the First Pier, is a bit more subdued, with less mainstream bars and fewer shops available. As you go southwest, the area becomes more and more lively, and finally brings you to the iconic White Tower.

The extraordinary rock formations and caves of Al-Qara are one of the most prominent landmarks in the Al Ahsa region and are well worth a dedicated day trip. Exploring the maze-like caves is a pleasant experience year-round; the caves remain cool during the summer and warm in the winter. The mountaintop offers unobstructed views of the lush palm oasis below. According to local legend, these caves are associated with the story of Judas Iscariot, who is said to have ended his life here after the biblical betrayal.

Aristotelous Square is the most impressive square in Thessaloniki. It features buildings with monumental architecture inspired by European and colonial models, cafes, shops and restaurants. It is the focal point in big celebrations, such as the coming of the New Year, and is the de facto meeting place during the day. The history of Aristotelous Square began with the Great Fire of 1917 that destroyed two thirds of the city. The French architect Ernest Hébrard designed Aristotelous Square to serve as an end of a monumental axis for Thessaloniki that would stretch from the seafront to Dikastirion Square and the Roman Forum. The final design, built in the 1950s, is a lot more stripped down than Hébrard's original proposal, but still has significant architectural value.