A Walk through Time
History of timekeeping from ancient to modern times.
Calendars through the Ages
Systems of counting the days, months, and years.
Daylight Saving Time
When and why do we change our clocks?
Illustrated mechanisms of many historical clocks.
It's About Time
Advances in timekeeping accuracy and atomic clocks.
(at University of Wisconsin)
Quartz Clocks and Watches
What's inside your wristwatch?
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commercial products by NIST or USNO.