Melusina

She is sitting on the left bank of the Alzette, looking across at the church, and she is the reason this city exists at all.

The story goes that when Count Siegfried bought the rock of the Bock in 963 and built his castle on it, he married a woman named Melusina. She asked one thing of him: every Saturday she would shut herself away, and he was never to look. He kept to it for years. Then, inevitably, he looked — and found his wife in her bath with the tail of a fish. At the sight of him she was gone, into the rock of the Bock, and the castle was never quite the same.

Luxembourgers will tell you she is still in there. Every seven years she comes up, sometimes as a woman, sometimes as a serpent with a golden key in her mouth, and if someone were brave enough to take the key from her she would be freed and the city would be hers again. Nobody has been brave enough yet.

The sculpture is recent. In 2013, for the city's 1050th birthday, Luxembourg ran a competition for a Melusina to stand in the Grund. Serge Ecker won it in February 2014, and made her not by casting but by 3D printing — a thousand-year-old legend built with a machine that didn't exist when the last version of her was carved. She was unveiled here in October 2015.