Not necessarily planets in this hypothetical! And there's lots of funky chemistry and conditions on the different worlds outside our own, even within our own Solar System. Titan, Saturn's largest moon, has an atmosphere thicker than ours + methane oceans! And I don't think anything on Earth can match the wild storms of Neptune, the hellish conditions of Venus, the beautiful rings of Saturn (would make for some sick astrophotography), or the dust storms of Mars.

Or maybe you could venture outside the Solar System, and see other stars, exoplanets, or maybe even more exotic objects, like black holes and neutron stars!