These immensely photogenic and relatable trees, their shaggy, sinewy limbs thrust upward into the pale light of the desert sky, are the main reason people come here to California"s Joshua Tree National Park. Joshua Tree was declared a national monument on August 10, 1936, before being designated a national park in 1994. Perhaps no other national park is so completely defined by a single feature, be it a plant or wildlife or natural formation. While Joshua Tree National Park contains other wonders, this tree that looks drawn by Dr. Seuss is what visitors come to celebrate.