What is recorded here

Hellsgate Island surfaces only when the tide pulls back, revealing a hidden gate where the Abbey River joins the Shannon. It is a submerged threshold in Limerick, named for the dangerous water and the city’s defensive history. Standing on it at low tide feels like touching the moment the river stopped being a boundary and became a road.

A island that appears at low tide but doesn't at high tide. The island can be found at the wiki page.

Hellsgate Island is a tidal island located in the Shetland Islands, Scotland, known for its dramatic sea arch that resembles a gateway, giving the island its name. It is notable for its geological features and as a site of historical Norse settlement in the Shetland archipelago.