https://slate.com/news-and-politics/2002/01/how-did-the-u-s-get-a-naval-base-in-cuba.html
The US took the area by force during the Spanish-American War, and then signed a “lease” with no end date with the Cuban government at the time.
I bet every time Cuba says they want to take it back, the US says “Yeah? You and what army?”
The price of very large publically traded companies is set entirely by supply and demand. Yes, those shares do represent a tiny share of ownership in the company, which means a share in the profits and assets of the company. But there is no law tying them together. Tesla’s market value is so high because there are more buyers than sellers, it’s as simple as that.