Atlas Obscura informs us that in 2017, what you see above was merely an old, graffiti-covered vent for an underground shelter meant to be used in the event of a nuclear war. It's located in Folimanka Park in Prague, the capital of the Czech Republic. So it would have provided air to survivors of a NATO nuclear attack upon communist Czechoslovakia.
We don't know who was responsible for the transformation, but they put a lot of work into the project, including adding concrete legs and R2-D2's iconic photoreceptor.
The Mayor of Prague was so pleased by the illegal but beautiful project that he ordered that it remain in place.
-via Street Art Utopia