A stronghold is a structure that occurs naturally underground in the Overworld, and is the only place where an end portal can be found. Strongholds can be located by using an eye of ender. Strongholds generate at any Y level, mostly underground, and prefer to generate in biomes above sea level, but generate underwater if necessary. Strongholds may generate at bedrock level, cutting the bedrock. Most parts of the stronghold can be overwritten by caves, ocean monuments, ancient cities…