Here's a nautical Geo Quiz for you.
There's a new study out about the risk of ocean pollution caused by shipwrecks.
There's everything from pirate ships that sank with chests full of gold to oil tankers that have gone down in more modern times at the bottom of the ocean.
Many of the vessels could be leaking something toxic into the sea.
The National Oceanic and Atmospheric Administration (NOAA) has come up with a map of the many, many shipwrecks that dot US coastal waters.
So here's question for you:
How many shipwrecked vessels are there off US coastlines?
Lisa Symons of the NOAA is in a good position to answer this question: About how many shipwrecks lie in US coastal waters?
She wrote the new study called "2012 Risk Assessment for Potentially Polluting Wrecks in US Waters" which identifies 20,000 (c) shipwrecks in US coastal waters.
Of those, NOAA pinpoints 87 ships, mostly sunk by German submarines during WWII that have the potential to leak millions of gallons of oil.