Petro is cryptocurrency issued by Venezuela. It's backed by cruse oil of that country.
That's an interesting concept and it's the first cryptocurrency issued by government.
The official website says "Petro is the first State-issued cryptoasset".
You can check below links if you want to participate in the sale.
https://en.wikipedia.org/wiki/Petro_(cryptocurrency)
http://www.elpetro.gob.ve/index-en.html