Is it alright for a DM to twist the major cities if the DM doesn’t know them very well?

If a polymorphed target is reduced to 0HP by the Immolation spell, does it turn to ash?

Tomb of Horrors a Steven Spielberg movie!

Adventurers!
I’m going totally mad.
I’ve discovered that Steven Spielberg is filming Ready Player One a film adaptation of Ernes Cline Novel.
If you have read the book you know that the first part is set in the most famous meatgrinder dungeon Tomb of Horrors by Gary Gygax!

My old bones are trembling, Acererack will be a movie star
The movie will released 30 march 2018 and I bet that Wizards are preparing something to revamp this epic dungeon… Tomb of Annihilation!