Law
The Doctrine of Rebus Sic Stantibus in Treaty Law
Quick fact
Rebus sic stantibus is enshrined in Article 62 of the Vienna Convention on the Law of Treaties, yet in practice it has almost never been successfully invoked to terminate a treaty, making it a 'safety valve' that is more powerful as a threat than as a tool.
Why this is interesting
You sign a contract to rent a beachfront property, but a rising sea swallows the land. Should you still be bound by the contract? International law has a surprising answer for treaties.