Indeed, this is kind of like the Sesame Street game of "Which thing doesn't belong?" And you're right to say it's the swimming pool that doesn't belong, because the swimming pool is the only thing on this slide that's actually very dangerous.
Stvarno, ovo je kao igra iz Ulice Sezam, "Koja stvar ne pripada?" I u pravu ste kada kažete da je bazen taj koji ne pripada, zato što je bazen jedina stvar na ovoj slici koja je zapravo vrlo opasna.