also about how much of a certain slope to count as a cliff. For example, given a truly vertical rock wall above a very steep slope, one could count just the rock wall or the combination. Listings of cliffs are thus inherently uncertain.

Some of the largest cliffs on Earth are found underwater. For example, an 8,000 m drop over a 4,250 m span can be found at a ridge sitting inside the Kermadec Trench. Or, some of the largest sea cliffs in the southern hemisphere exist both above (300 m) and below