Excerpt:
The Time and Frequency Division, part of NIST's Physics Laboratory, maintains the standard for frequency and time interval for the United States, provides official time to the United States, and carries out a broad program of research and service activities in time and frequency metrology.
Annotation:
This site provides links to a few time and calendar exhibits and hosts two exhibits itself. These hosted exhibits, "A Walk Through Time," and "NIST's work measuring time & frequency" are interesting but not particularly deep. The Time and Frequency exhibit provides information about early radio history in the United States as well as information about clock synchronization, the atomic clock and the Global Positioning System. The Walk Through Time exhibit provides a brief synopsis of six periods in history during which the measurement of time evolved from calendars, to sun dials, to mechanical clocks, to internet time synchronization.