Underground Moon Caverns
The Underground Moon Caverns, known colloquially as the Moon Cave, is one of the largest sub-worlds in the game and can be found in the Moon Kingdom. The level, which contains a total of five Power Moons and 18 regional coins, is a gauntlet of many different game mechanics and capture types and culminates in a rematch against Madame Broode. Traversing the level is intended to be a requirement to beat the game, but the famous Moon Cave Skip speedrun trick allows the entire interior to be skipped, which can save up to two minutes or more in some speedruns.