Walk on the Stromatolites

Greenfield Center, New York

Experience the thrill of walking on a "fossilized sea bottom" next to a modern suburban road. With its own historical marker and informational signs, this part of New York state -- now identified as the tiny Lester Park -- was a shallow tropical sea 490 million years ago, when it lay south of the equator. The property was donated to the New York State Museum in 1914.

The round shapes and swirly patterns in the sea-bottom rocks are stromatolites, or "sea cabbages," formed in very shallow waters by blue-green algae. They are the oldest evidence of life on Earth. Tucked among the cabbages are fossilized marine animals such as snails, trilobites, and brachiopods. Visitors are prohibited from taking any fossils, but it's perfectly okay to walk all over the ancient yet sturdy stromatolites, as it's the only way to see them, and to get to the informational signs.