Ice carousel

An ice carousel is a circular piece of ice made to spin like a carousel within a larger body of water, often a frozen lake. It is a man-made phenomenon, made by cutting the floating ice sheet, unlike the natural rotating ice circles.
History.
In 2017, Janne Käpylehto carved one in Lohja, in Finland. 
Two men created one in Burntside Lake, near Ely, Minnesota, in 2018.
An ice carousel created in Little Falls, Minnesota in early 2019 was dubbed the largest in the world.
In December 2019, on a lake in Clerval, Abitibi, Québec, Canada, a team constructed an ice carousel with a diameter of and an area of , surpassing the prior record of set in the United States. The feat was recognized by the World Ice Carousel Association, which keeps track of records.
An even larger ice carousel was cut into Lake Lappajärvi in Finland by Janne Käpylehto's team in March 2021. The carousel has a diameter of and the ice is thick, giving the carousel an estimated mass of 30-40 000 tons. The team included the mayors of the three towns surrounding the crater lake.