The La Brea Tar Pits are a group of tar pits located in Los Angeles, California. They are one of the most famous fossil sites in the world, and have been a source of scientific research since the late 19th century. The tar pits are composed of asphalt deposits that were formed from natural oil seeps that occurred over 40, 000 years ago. The tar pits are home to a variety of fossils, including those of saber-toothed cats, mammoths, dire wolves, and other extinct animals. The term 'La Brea Tar Pits' is derived from the Spanish phrase 'la brea, ' which means 'the tar.' The four-letter answer to the crossword puzzle is 'PITS.'