Lubeck

Lubeck is one of those rare UNESCO old towns where the headline sights cost nothing: the whole medieval core sits on one walkable island, so wandering it is the main event and it is free. The postcard view of the Holstentor gate and the old salt warehouses, the seven church towers on the skyline, and the restored sailing ships along the Museumshafen harbour front all cost nothing from the outside, and the maze of romantic Gänge and Höfe (the hidden alleys and old foundation courtyards) is open to anyone willing to poke around. Some of the great brick Gothic churches now ask a small upkeep contribution to step inside, but the exteriors, the towers on the skyline, and the streets themselves cost nothing, so a self-guided walk past the big names runs to nearly zero before you stop for a slice of Niederegger marzipan. Lubeck is also a cheap regional-train hop from Hamburg, which makes it an easy budget day trip rather than a separate hotel bill, and the Baltic beach at Travemunde sits at the mouth of the same river for a free sand-and-sea afternoon. Aim for late spring or September: the light is good, the Baltic-coast crowds and room rates have not peaked, and the old town is at its quietest.