In Spanish, if you ask "where from?" you'd say "¿De dónde?", which is also a triple composition.

The adverb "dónde" already has the preposition "de" embeded in it, as it comes from a condensation of Vulgar Latin "de unde", already meaning "from where". But Latin "unde" already is a composed form meaning "from where", and where the "-de" ending is not the preposition "de" but it's still a particle making "unde" a composed form...

So if you're Spanish and ask "¿De dónde?" you're asking

¿(from (from (where from)))?