At 2 a.m. local time on Sunday, Nov. 1, U.S. residents will set their clocks back one hour for daylight savings time.

According to National Geographic News, a federal law was passed in 1918 to ensure that clocks would "fall back" one hour on the first Sunday in November.

Daylight savings time originally started when the time zones for railroad travel were determined - also a part of the 1918 DST law.