From Sahih Bukhari (Hadith 5493):
Narrated Jabir:We went out in a campaign and the army was called The Army of the Khabat, and Abu 'Ubaida was our commander. We were struck with severe hunger. Then the sea threw a huge dead fish called Al- `Anbar, the like of which had never been seen. We ate of it for half a month, and then Abu 'Ubaida took one of its bones (and made an arch of it) so that a rider could easily pass under it
Reference: Bukhari 5493