Yolochki, Razvodnaya St., Saint Petersburg, Russia, 198510
"The 'Fir Trees' Joke" – a group of three small metal trees that spray water, located in one of the clumps near the Orangery. The original fountain was created in 1784 by masters Keyzer and Strelnikov. The fir trees are situated in a clearing south of the Oak Grove and represent three metal trees, which are very difficult to distinguish from real firs. When well-dressed guests passed by, suddenly jets of water would splash the ladies and gentlemen.
Consisting of connected tubes shaped like trunks and branches and covered with wire "needles," these "trees" can initially be mistaken for real firs, but as soon as you approach them, thin streams of water start shooting from the branches, revealing their playful intent. The water from beneath the fir trees flowed into a small pond, which was formerly used as an aquarium.
Currently, water flows continuously from the branches, so the streams are completely harmless to park visitors.
Destroyed during the war, the fountain complex "Fir Trees" was recreated in 1958 by the fountain mechanic Smirnov's team based on surviving drawings from 1828.
Sources:
https://www.spb-guide.ru/fontany-shutihi-elochki-petergof.htm
https://peterhofmuseum.ru/objects/peterhof/fontan_shutiha_elochki