This "door" is entry to the water tower (from 1895) at Holešovice Market.
Unfortunately lots of Prague´s water towers are unused. Hopefully this one (otherwise very nice) will be renovated in future.
This is a part of St. Štěpán Church. It was built in 14th century. But in next centuries it was rebuilt (like most of old churches). And this is one of the reconstructions - bricked up doors.
Toto je část kostela sv. Štěpána. Byl postaven ve 14. století. Ale v dalších stoletích byl přestavován (jako většina starých kostelů). A toto je jedna z přestaveb - zazděné dveře.