This is a bit of a stretch but your description kinda reminds me of 'Kingdom of the Crystal Skull', even though it's an Indiana Jones film and came out in 2008. Maybe you're mixing up the date? Other than that, I can't really think of many adventure films with an ancient city that aren't part of a bigger franchise 🤔

I'm racking my brain but nothin'. Maybe something called 'The Pyramid'? Sorta fits with the ancient theme. Wasn't there like a mechanic where they had to figure out traps and puzzles?

The Lost City sounds like what you're after. It's not super famous or anything, but definitely had that adventure feel you're talking about. They don't make a lot of those types anymore, sans the major franchises. The film flew under the radar for most people, but it had a pretty cool plot and decently executed effects for its budget. Not sure about the exact year though, might want to dig around a bit.

lol ancient cities are so last century. was it indiana jones and the retirement home of doom by any chance?

What about that ‘The Mummy’ reboot? I think it had an ancient city and some traps. That Tom Cruise one? Could that be it?

Okay, based on what you said - explorers, ancient lost city, adventure thriller...booby traps and decoding - this sounds a whole lot like 'Uncharted'. Wait, that's a game... Ah, but they announced a movie adaptation, didn't they? Although its release date was beyond 2018, your description fits the game's theme, so maybe you confused the game hype with the movie release?

Hmm... your description is kinda vague, but have you checked out 'The Lost City of Z'? It came out in 2016 and it's about exploring the Amazon for a lost city. Not sure about the booby traps though.

Sounds like you might be talking about 'As Above, So Below'. Its got the whole ancient city vibe since they go into the catacombs under Paris, which is kinda like an ancient city. Plus it's got the decoding and traps stuff you mentioned!