not in Kansas anymore

From the film The Wizard of Oz (1939), in which Dorothy states, “Toto, I've a feeling we're not in Kansas anymore.”

• "As soon as I walked into that party I thought, "I'm not in Kansas anymore.""
• "John Crosbie? A Tory government? You could be forgiven if your first reaction was the feeling that you weren't in Kansas anymore."
• "The police action is rough and raw, like Hill Street Blues. But when a courtroom jury, asked for its verdict, breaks into song, we know we're not in Kansas anymore."
• "C++ meets all three of these classic criteria of object-orientedness, but once you really start to take advantage of them in your programs, you'll find you're definitely not in Kansas anymore."

• out of one's depth

• you can't go home again