"THE STACK"

The Four Level Interchange (also known as “The Stack”, but officially named the Bill Keene Memorial Interchange) was the first stack interchange in the world. Completed in 1949 and fully opened in 1953 at the northern edge of Downtown Los Angeles, it connects U.S. route 101 (Hollywood Freeway and Santa Ana Freeway) to State Route 101 (Harbor Freeway and Arroyo Seco Parkway). The interchange is officially named in memory of Los Angeles traffic and weather reporter Bill Keene.
LEVEL 1	Curved ramps for those changing from the 110 to the 101
LEVEL 2	Main trunk of the 110, named the Arroyo Seco Parkway north of the interchange and the Harbor Freeway south of it
LEVEL 3	Arcing flyover ramps carrying traffic from the 101 to the 110
LEVEL 4	Main trunk of the 101, named the Hollywood Freeway to the west and the Santa Ana Freeway to the east

THE FOUR LEVEL INTERCHANGE AS SEEN FROM ABOVE IN 1959