Huge Cave System Under a Cherry Mountain

Minecraft Seed: 938080115534820641

You spawn on a cherry mountain. Not far away, there is a cave opening in the mountain. Go inside and you will see the biggest cave system you have ever seen.

There is also a whole ancient city under it.

Tested on Minecraft 1.20.1 (Forge, OptiFine) using TLauncher, with no mods.