You are watching at photos of abandoned Soviet Military Navy repair factory in Estonia. It is placed at Arkula, near Tallinn. This is another one abandoned Soviet military building which once used to be an instrument in Cold War race with United States.
When Cold War ended Russia and rest of Soviet countries changed their military politics and plenty of similar facilities became useless so they had to simply abandon them leaving plenty of military equipment and arms.
You can see here a few of photos which are telling us that this facility also could contain some dangerous biological weapon. However, that fact does not stop kids from local villages to play with that abandoned but very dangerous equipment.