Fallas 

Or Falles... What's the deal with people and burning things? Fallas might be (among) the biggest build-things-just-to-burn-them customs, but it's far from the only one. On one of our islands, they build a ship just to burn it as a part of the St. Nicholas celebration. There are all those carnival puppets that get ceremonially burned every year. Bonfires lit on various (paganistic) occasions don't quite go that far in the elaborateness of the thing burned (although they can more than compensate for that in sheer size), but it's still people being merry around things that are on fire.

We like destroying things in spectacular ways, don't we?