The Hat of Lou Bandy

The Dutch city of Rotterdam was nearly completely destroyed during World War II and left as rubble, after which it was quickly rebuilt by erecting many concrete shoebox-style buildings. To counter this impersonal and monotonous architecture, a group of artists decided to create a bunch of interesting and offbeat art installations to liven up the city. 

The Kunst en Vaarwerk artist collective has developed a few influential pop art pieces around Rotterdam over the last few decades, and one of their best-known creations is the "Hat of Lou Bandy." Created in 1985, the piece takes the form of a giant Oxford 1896-style straw hat floating upside-down in a lake.

The oversized hat (named for the popular Dutch singer who often donned such a hat) rests slightly askew above the water in the lake at Vroesenpark, giving the impression of a lost hat that blew off of someone's head and fell in the water.

From afar, it looks like a normal-sized hat, but when looking closer you'll notice that it is in fact much bigger than expected. It gives a very strange parallax effect when walking by, piquing the curiosity of the beholder.