Floating island

island (natural or artificial) made of floating plants, mud, and peat

A floating island is a large mass of organic particles that float on the surface of a water body. Floating islands occur naturally, but some are artificial. Naturally occurring floating islands include icebergs and pumice rafts. Their thickness varies from a few centimetres to a few metres. Floating islands are generally found on marshlands, lakes, and similar wetland locations, and can be many hectares in size.

Floating island, on a lake in Germany.