Events

• Emperor Justinian II of the Byzantine Empire defeats the Bulgarians.
• King Caedwalla of Wessex abdicates the throne and goes on a pilgrimage to Rome.

Births

• Charles Martel, Mayor of the Palace of the Kingdom of the Franks (approximate date)

Deaths

• Perctarit , king of the Lombards

688 is also the hull number of the US Navy attack submarine USS Los Angeles. The number has come to be a shorthand reference for all of the many submarines of the Los Angeles class. For instance, 688 Sub Attack is a computer game about submarines.