The Scottish Cafe in Lvov
The original Szkocka Café (Scottish Café) in Akamemichna in Lvov, Ukraine,
now the Desertniy Bar at T. Shevchenko Prospekt 27.
At various times Lvov has been known as L'vov, Lviv, L'viv, Lwow and Lemberg.
The café was a meeting place for many mathematicians including Banach, Steinhaus, Ulam, Mazur, Kac, Schauder, Kaczmarz and others. Problems were written in a book kept by the landlord and often prizes were offered for their solution.
A collection of these problems appeared later as the Scottish Book.
R D Mauldin, The Scottish Book, Mathematics from the Scottish Café (1981) contains the problems as well as some solutions and commentaries.
You can see more about the Scottish Book at THIS LINK