Soviet Hero Cities

[matteti]

Hi all dear knowledgeable friends!
I have a question that is bothered me for some time. It's about "Hero Cities". On the main site, under the header for the medal For Defence of Odessa, we can read "Odessa was awarded the Title of "Hero City" on 1 May 1945, and is one of only four "Hero Cities" in the USSR (the others being Leningrad, Stalingrad, and Sevastopol.)

What does that mean? Are there only 4 Hero cities? Or only four of them were declared Hero Cities on May, 1 1945?

Because, if I remember correctly from when I visited the Memorial Museum of War in Kiev, there are many big monuments (around 15) to the Hero Cities which shows a giant HSU order on them and the name of the cities under. There was Kiev, Moscow, Minsk, Odessa, Sevastopol, Leningrad, Brest, Stalingrad, and some others that I just don't remember at the moment.

Also, on Internet, I often saw a list of Soviet Hero Cities that was lot more extensive.

So, can someone explain to me what I should understand?

Thank you very much in advance.

P.S. I don't write often, but it's always a great pleasure to read you on a daily basis and learn from your interesting posts.