There is now an exhibit at the National Archaeological Museum in Athens featuring the Antikythera mechinism, and many artictic replicas of how the mechanism may have looked and worked.

A roman-era shipwreck that contained the Antikythera mechanism. It was discovered around Easter of 1900.

Da Vinci's unusual sleep pattern (3.5 hours awake, followed by 30 minues asleep) may have pushed him to develop an alarm clock. His design was based on a water clock, and included set amounts of water that were dropped into a resevoir, which when full would activate several levers that propped his legs up, and woke him.

His plans and sketches for this devide were found in his Codex Madrid.

The Clock in St. Mark's Clocktower is an excellent example of the development of clockwork over the years. Inaugurated in 1497, it used weights and a Verge and Foliet escapement, and showed the 24 hours of the day (Italian style), the relative positions of 5 planets, the moon's phases, and the position of the sun in the zodiac. It required a clock-keeper to manage and maintain the clock.