[McGruff]

Perhaps they should have held on to them: Hundreds of rusting tanks abandoned in secret Ukrainian depot unveiled as Russia's armoured vehicles line its streets

There are more than 400 abandoned tanks at the plant in a secret, heavily guarded depot in the town of Kharkiv

https://www.dailymail.co.uk/news/article-2572149/Stunning-images-huge-abandoned-tank-graveyard-Ukraine-machines-come-retirement-tensions-Russia-continue-escalate.html

[PIF]

If you think that’s big you should see the size of the tank depots in the Far East. If someone wanted to it looks like that place could easily be Geo-located do not really a secret, nor from drones, or satellites.