To celebrate the 500th anniversary of the founding of the port on the right bank of the Seine estuary, Le Havre went big. They commissioned a sculpture from artist Vincent Ganivet... and he delivered a monument!
Standing at nearly 29 m tall, the arches are made with 36 shipping containers, representing Le Havre's half-millennium as an international trade hub. 21 in one and 15 in the other, they are arranged in a catenary shape which makes the structure self-supporting. There's stuff to satisfy a maths and physics buff in there somewhere... but I'll just concentrate on the fact that it looks cool, especially compared to its industrial and brutalist surroundings.
As a major port in Nazi-occupied France, Le Havre was bombed into oblivion by the Allies, hence most of the town centre's buildings were built at once in the late 1940s-early 1950s. The result is a very rigid, homogeneous, mineral urban environment, to which the Catène adds a welcome dash of colour.
But if nothing else (and we've established there is a lot else), it looks like it'd make a compelling Mario Kart track.