<human>:  When did the first humans arrive in the Americas?
<bot>: The first humans arrived in the Americas around 12,000 years ago. They came from Asia and traveled across the Bering land bridge that connected Siberia to Alaska. The Bering land bridge is a low-lying land bridge that connects Siberia to Alaska, and it was likely dry land at the time. The land bridge was covered by the sea at least once during the last ice age, and the sea level dropped enough to expose the land bridge, allowing humans to walk across it.