The hot spring emoji shows that it is full of hot water. It normally refers to taking a hot bath in either a hot spring or tub. This symbol is often used to indicate the location of an Onsen or hot springs in maps.
NOTE: Hot Springs was accepted in 1993 as part of Unicode 1.1 and in 2015 added to Emoji 1.0.
♨️ Hot Springs
:hotsprings: (Github, Slack)