The first thing Estonians did after regaining independence in August 1991 was to remove as many symbols of Soviet power as they could find, but a few reminders of that time are still with us.
My favorite one is a colossal Stalin era building on Tartu street with a spire and star at the top. There’s nothing special about the house itself (it was just a residential building), but it is the strongest representative of that style in Tallinn. You can find it by going to the Stockmann department store and looking across the road.