GUM - Glavnyi Universalnyi Magazin, meaning Main Universal Store
(or Gosudarstvennyi Universalnyi Magazin, meaning State Department Store during the Soviet times).
Many cities in the former Soviet Union had a GUM. This is the most famous one, built in 1889-93,
and is actually a shopping mall, once with more than 1000 shops, though currently numbering about
200 (mostly high-priced western fashion shops such as Christian Dior, Hogo Boss, Estee Lauder, etc).

The first time I visited Moscow, in 1977, GUM was a collection of small stores, each selling but one
or two items, and often with very little stock. One store I visited sold only poor quality soap.
You had to queue to ask for what you wanted, then go to another counter and queue again to pay, then
return to the soap counter to collect your purchase. Every purchase required standing in three different lines!
Now the mall is well-stocked with high-fashion goods that very few can actually afford.