Alligator Alcatraz' immigrant detention center poses serious risks, including hurricanes, flooding, and mosquitoes, experts say.

People are there,” Press Secretary Jae Williams said, though he didn’t immediately provide further details on the number of detainees or when they arrived.

The first group of immigrants has arrived at the center in the Florida Everglades. It was built in eight days and could eventually hold 3,000 people. (AP Video: Rebecca Blackwell)