Wikipedia:Selected anniversaries/July 27
- 678 – Unable to penetrate the city's defences, the Sclaveni were forced to give up their siege of the Byzantine city of Thessalonica.
- 1302 – Byzantine–Ottoman wars: The Ottoman sultanate gained its first major victory against the Byzantine Empire at the Battle of Bapheus in Bithynia.
- 1955 – The Austrian State Treaty came into effect, ending the Allied occupation of Austria, although the country was not free of Allied troops until October.
- 1983 – Madonna (pictured) released her self-titled debut album, which set the standard for the genre of dance-pop for decades.
- 2007 – While covering a police pursuit in Phoenix, Arizona, two news helicopters collided in mid-air, killing both crews.