Please answer the following question: Generate a question that has the following answer: July 20, 1969 for the following movie plot: On July 20, 1969, astronaut Jim Lovell hosts a house party where guests watch on television as Neil Armstrong takes his first steps on the Moon. After the party, Lovell, who had orbited the Moon on Apollo 8, tells his wife Marilyn that he intends to return to the Moon and walk on its surface. On October 30, 1969, as Lovell conducts a VIP tour of NASA's Vehicle Assembly Building, his boss Deke Slayton informs him that he and his crew will fly the Apollo 13 mission instead of Apollo 14. Lovell, Ken Mattingly, and Fred Haise train for their new mission. Days before launch, Mattingly is discovered to have been exposed to rubella, and the flight surgeon demands his replacement with Mattingly's backup, Jack Swigert, as a safety precaution. Lovell initially resists breaking up his team, but relents when Slayton threatens to bump his crew to a later mission. As the launch date approaches, Marilyn has a nightmare about her husband's safety, but goes to the Kennedy Space Center the night before launch to see him off. On April 11, 1970, Apollo 13 Flight Director Gene Kranz gives the go-ahead from Houston's Mission Control Center for launch. After the Saturn V rocket climbs through the atmosphere, an engine on the second stage cuts off prematurely, but the craft still reaches its Earth parking orbit. After the third stage re-fires, sending Apollo 13 to the Moon, Swigert docks the Command/Service Module Odyssey with the Lunar Module Aquarius and pulls it away from the spent stage. Three days into the mission, the crew sends a live television transmission from Odyssey, which the networks decline to broadcast live. After Swigert performs a standard housekeeping procedure, one of two liquid oxygen tanks explodes, emptying its contents into space and sending the craft tumbling. The other tank is soon found to be leaking. Mission Control aborts the Moon landing, Lovell and Haise hurriedly power up Aquarius as a "lifeboat" for the return home, and Swigert shuts down Odyssey before its battery power runs out. In Houston, Kranz...
A:
On what day did Neil Armstrong walk on the moon?