Scientists have discovered the largest virus in the world in the ocean off the coast of Chile. The Megavirus Chilensis measures around 10 to 20 times the length of the average virus – or about 0.7 micrometers (thousandths of a millimeter) in diameter. It likely infects single-cell marine amoebas, which float around in the ocean, and was found off Las Cruces, in central Chile during a biology trawl.