This unusual cathedral was built in Moscow in the 16th century on the orders of Ivan the Terrible. According to legend, the Tsar had the architects blinded so that they could not reproduce their work elsewhere. It seems that this is not true! Note that the cathedral is in fact a grouping of 9 chapels around a main church.
Here's a typical close-up view.

https://www.nationalgeographic.fr/voyage/2021/08/la-cathedrale-saint-basile-le-bienheureux-joyau-architectural-moscovite
Difficulty ***