Which planet has the tallest mountain?

since when is Ceres a planet in our solar system and Pluto lost that status some years ago

thats hard to even fathom!! guessed right though!!

Jecca, As of 2015, we have performed flybys of all the planets, including the dwarf planet, Pluto. If you mean that we haven't landed on them, obviously, a landing would never be possible on Jupiter, Saturn, Neptune and Uranus.

Flutterby, they were trying to confuse us

how can this be correctly answered, when we haven't even had any exploration on at least four of these planets Milky Way?

Those planets are not to scale.

Player #2342698, I am definitely not going fathom it,. I am just going to believe it.