Sahih Muslim Book 6, Hadith Number 2470.

Chapter : Permissibility of observing the fast or not observing it in the month of Ramadan for a traveller.

Ibn ‘Abbas (Allah be pleased with him) reported that the Messenger of Allah (may peace be upon him) journeyed during the month of Ramadan in a slate of fasting till he reached ‘Usfan. He then ordered a cup containing drinking water and he drank that openly so that the people might see it, and broke the fast (and did not resume it) till he reached Mecca. Ibn ‘Abbas (Allah be pleased with him) said: Allah’s Messenger (may peace be upon him) fasted and broke the fast, so he who wished fasted and he who wished to break it broke it.