While I know there are plenty of examples of land, particularly historically, being bought and sold to other countries. Like Alaska was bought from Russia, the US Virgin Islands from the Dutch, etc. But is there any examples, particularly in semi-modern history, of an **individual** buying sovereignty over a piece of land from another nation? I mean why should the country care who they sell to as long as they get the money.

I figure the hard part would be defending the land as a single owner. Of course in practice im not sure countries sell land all to often these days. 

 There is Sealand, although it was not purchased from the UK.

https://sealandgov.org/en-us