Simplify the following text for a Grade 8 native English-speaking person.
Original: In 1925 , for example , Knight produced an elaborate mural for the Natural History Museum of Los Angeles County which portrayed some of the birds and mammals whose remains had been found in the nearby La Brea Tar Pits .
Simplified: In 1925 Knight produced an elaborate mural for the Natural History Museum of Los Angeles County . This illustrated some of the birds and mammals whose remains had been found in the nearby La Brea Tar Pits .