In a tradition that goes back to Yuri Gagarin and the Soviet space program, each cosmonaut crew member has planted a tree before their departure at the Baikonur Cosmodrome.
The trees are located behind the Cosmonaut Hotel, which was designed for cosmonauts to rest before their space travels. The grove lines the Avenue of the Cosmonauts, as it's called, and each is designated with a plaque with the crew member's name and the year.
Gagarin's tree stands the tallest, while recent Soyuz crews have smaller saplings growing from the soil. A planting traditionally takes place the day before a voyage, although it can also be the week before, and it's accompanied by a walk in the grove to remember the intrepid cosmonauts who came before through the trees that flourish in their absence.