The Mount Wilson observatory actually came before the Palomar telescope. The Mount Wilson is where Hubble first determined the distance to the Andromeda galaxy(our closest major galaxy and gravitationaly bound with us as well! Actually, the Milky Way and Andromeda will someday collide and eventually become one system; sorry for those who know this). Hubble then found the galactic redshifts. The Palomar Telescope was suppose to take us to the edge of the observable universe. Well, we were wrong about that; we hoped the Hubble space telescope would, and now the James Webb; well, what of it?!
Anyways, the Palomar telescope is kind of the first fully functional astronomer telescope. It didn't have to worry about the weather quite like the Mount Wilson mirror. The Palomar telescopes mirrors were made out of a different material that doesn't change shapes due to temperature all that much. The the telescope was so big, it needed 'arches' of metal to keep it up and in the right position. The Palomar telescope was considered the biggest you could make telescopes for that last reason. Nobody thought we could support a bigger telescope; then came segmented mirrors of Keck . . . ; The Palomar telescope also had lots of sophisticated electronics(for its time). When you realize this was being built in the 1930s, and completed in the 1940s(due to world war 2), you realize how technologically advanced this telescope was for its time.
I've been to Mount Palomar telescope many times. As you go there, you think, "Oh, it's not that big." You think that all the way till your standing right next to it; i mean literaly nose to wall and look up; that's when you realize no single man could have built this; this was a Pyramid; a pyramid of science! A functional temple, arch!