![male](https://img.y8.com/assets/avatars/male/1-48x48-e7b70373a1323b243c41013c1b94a59a49290351d82a1e9207eba857efefe616.png)
调整屏幕的大小
![Grand Falls Arizona](https://img.y8.com/cloud/y8-thumbs/213687/video_thumbnail.jpg)
人类判断
Grand Falls was formed when lava from nearby Merriam Crater flowed into the Little Colorado River creating a lava dam. The river was forced to reroute itself around the dam and Grand falls formed where the reroute rejoins its original course.