U.HOLU hole

a small depression of the sea floor

18 features in 12 countries.

#CountryFeaturesShare of the world
1BahamasBS4
2United KingdomGB4
3AustraliaAU1
4BermudaBM1
5BelizeBZ1
6EgyptEG1
7GreeceGR1
8JapanJP1
9Northern Mariana IslandsMP1
10MaltaMT1
11Turks and Caicos IslandsTC1
12United StatesUS1
Total18