Many medieval artists painted what's known as the Hellmouth (literally the mouth to hell). Imagine if this Hellmouth went to the dentist, what that unsuspecting doctor would find living/decaying in those gums!
Many of our notions of hell come from Dante's Inferno, which is total badness. Lucifer resides in the ninth circle of hell, which, counterintuitively, sits on a frozen lake. Hey, he's Lucifer: he can afford A/C.
Flemish artist Bruegel did this depiction of Hell in the 16th century. It kind of looks like a bunch of semi-human revelers getting freaky with it in an events hall. That's one place where instead of selfies people take hellfies.
In the Hortus deliciarum, a medieval book, Hell kind of looks like an apartment complex. Except your neighbors are screaming all the time, and your landlord is a pain in the butt. Oh wait, that's just like an apartment complex.
And of course, how could we forget one of the more definitive depictions of hell on the cover of Meatloaf's hit album. If there is a hell, hopefully it's filled with the sweet jams of 1970's rock...forever!!