Can you imagine a database that stands as much traffic as you want, adding and removing nodes automatically, working interruption-free even if a volcano starts spitting lava over your data centres? That's the promise of distributed systems like Cassandra, Voldemort or Riak. But, how do they do it? In this talk I will tell you the basics of distributed databases. Come to my talk if you want to learn about CAP, BASE, incremental scalability, replication or consensus. I will also explain geeky things like gossip, vector clocks, hinted handoff, or entropy.