Two days before deadly Central Texas floods killed at least 27 people at Camp Mystic, a state inspector certified that it had an emergency plan in place and that its cabins and other buildings were safe.

Camp Mystic was overrun by flash flooding that started on Independence Day. Rapidly rising waters ripped through the century-old all-girls Christian summer camp, killing at least 27 people. Others are still missing.

One of Texas' most popular rivers flooded over the weekend and contributed to Texas' catastrophic flooding that claimed over 80 lives, including two dozen children at Camp Mystic. Here's what to know about the layout of the river and the role it played in one of the state's deadliest flash floods in modern history.