Year 1940 (MCMXL) was a leap year starting on Monday (link will display the full calendar) of the Gregorian calendar.

Below, the events of World War II have the "WWII" prefix.

Justin Drew Bieber ( /ˈbiːbər/ BEE-bər, born March 1, 1994) is a Canadian Pop/R&B singer-songwriter, musician, and actor. Bieber was discovered in 2008 by Scooter Braun, who came across Bieber's videos on YouTube and later became his manager. Braun arranged for him to meet with Usher in Atlanta, Georgia, and Bieber was soon signed to Raymond Braun Media Group (RBMG), a joint venture between Braun and Usher, and then to a recording contract with Island Records offered by L.A. Reid. Bieber's debut single, "One Time", was released in 2009 and peaked in the top twenty in Canada and charted in the top thirty in several international markets. His debut album, the seven-track EP My World, followed in November 2009, and was soon certified platinum in the United States. He became the first artist to have seven songs from a debut album chart on the Billboard Hot 100.

Onika Tanya Maraj (born December 8, 1982), known by her stage name Nicki Minaj ( /mɪˈnɑːʒ/), is a Trinidadian-born American rapper and singer-songwriter. She was born in Saint James, Trinidad and Tobago and when she was 5 years of age she moved to the New York City borough of Queens, where she grew up.

After releasing three mixtapes between 2007 and 2009 and being signed to Young Money Entertainment in August 2009, Minaj released her debut album, Pink Friday, in November 2010. It quickly became a commercial success, peaking at number one on the U.S. Billboard 200 and being certified Platinum by the Recording Industry Association of America (RIAA) a month after its release. She became the first female solo artist to have seven singles on the Billboard Hot 100 at the same time. Her second single, "Your Love", reached number 1 on the Billboard Hot Rap Songs chart, making Minaj the first female artist to top the chart unaccompanied since 2002. She also became the first female artist to be included on MTV's Annual Hottest MC List. Minaj was named the 2011 Rising Star by Billboard. Her second studio album, Pink Friday: Roman Reloaded was released on April 3, 2012.