People attend the 4th annual Dino Fest at the Natural History Museum of Los Angeles, Los Angeles, the United States, Sept. 21, 2019. The two-day festival kicked off here Saturday, attracting hundreds of dino enthusiasts of all ages to the Museum. (Photo by Qian Weizhong/Xinhua)

People attend the 4th annual Dino Fest at the Natural History Museum of Los Angeles, Los Angeles, the United States, Sept. 21, 2019. The two-day festival kicked off here Saturday, attracting hundreds of dino enthusiasts of all ages to the Museum. (Photo by Qian Weizhong/Xinhua)

People attend the 4th annual Dino Fest at the Natural History Museum of Los Angeles, Los Angeles, the United States, Sept. 21, 2019. The two-day festival kicked off here Saturday, attracting hundreds of dino enthusiasts of all ages to the Museum. (Photo by Qian Weizhong/Xinhua)

People attend the 4th annual Dino Fest at the Natural History Museum of Los Angeles, Los Angeles, the United States, Sept. 21, 2019. The two-day festival kicked off here Saturday, attracting hundreds of dino enthusiasts of all ages to the Museum. (Photo by Qian Weizhong/Xinhua)

People watch a T-rex fossil at the 4th annual Dino Fest at the Natural History Museum of Los Angeles, Los Angeles, the United States, Sept. 21, 2019. The two-day festival kicked off here Saturday, attracting hundreds of dino enthusiasts of all ages to the Museum. (Photo by Qian Weizhong/Xinhua)

People attend the 4th annual Dino Fest at the Natural History Museum of Los Angeles, Los Angeles, the United States, Sept. 21, 2019. The two-day festival kicked off here Saturday, attracting hundreds of dino enthusiasts of all ages to the Museum. (Photo by Qian Weizhong/Xinhua)

People attend the 4th annual Dino Fest at the Natural History Museum of Los Angeles, Los Angeles, the United States, Sept. 21, 2019. The two-day festival kicked off here Saturday, attracting hundreds of dino enthusiasts of all ages to the Museum. (Photo by Qian Weizhong/Xinhua)