The deepest known point on dry land is a cave more than two kilometres straight down

Krubera Cave, also called Voronya Cave, sits in the Arabika Massif of Abkhazia in the Western Caucasus. Cavers first passed the 2,000-metre mark in 2004, and the latest survey puts its full explored depth at over 2,200 metres, making it the deepest known cave on Earth — a title it has held, with one brief interruption from a nearby rival, since 2001.

— Wikipedia contributors, Krubera Cave — Depth surveys, 2004–2024