What did New York look like in 1609?

The Manhatta Project looks to rediscover the natural history of New York City circa 1609, the year Henry Hudson identified the site for the Dutch East India company.

National Geographic also has a nice online series depicting the differences between what today's New York City looked like 400 years ago.

Also of note is the project's 'sponsor a block' page.  I highly recommend it for anyone in the non-profit centre looking for interesting ways to harness the internet for fundraising purposes.