William Manley used a Geographic Information System (GIS) to create a movie showing how the Bering Land Bridge evolved after the Last Glacial Maximum, about 21,000 years ago. Global sea level at that time was approximately 120 m (400 ft) lower than today. The Land Bridge existed as a vast tundra plain connecting Asia and North America. As the world's glaciers and ice sheets melted over the following thousands of years, rising sea level flooded the Land Bridge - blocking migration routes for animals and humans. The visualization was created in the INSTAAR Quaternary GIS lab and is based on the best available digital information; it reveals large-scale patterns of shifting coastlines and environments as the land bridge evolved.