Did You Know? The Cambrian seas of the Grand Canyon were home to several kinds of trilobite, whose closest living relative is the modern horsehoe crab. They left their fossil record in the mud of the Bright Angel Shale over 500 million years ago. more...
Did You Know? Tumacácori National Historical Park is located in the historic Pimería Alta or "Land of the Upper Pimas," an area that includes much of present-day southern Arizona and northern Sonora, Mexico. more...