Royal Observatory Greenwich holds a treasure trove of some of history's most iconic timepieces. Discover the stories behind John Harrison's groundbreaking marine chronometer H1, Charles Shepherd's 'master clock', and the famous Greenwich Time Ball. Plus, find out about the history of timekeeping and its importance to society.

When do the clocks go forward in 2021?
Marking the start of British Summer Time, the clocks 'spring forward' in March, meaning we'll lose an hour's sleep
When do the clocks go back in 2021?
Marking the end of British Summer Time, the clocks go back in October, giving us an extra hour in bed. But why do the clocks change?
Which years are leap years and can you have leap seconds?
Because the Earth takes a little over 365 days to orbit the Sun, we need to make adjustments to keep the seasons from drifting: leap years and even leap seconds.
20 May 2016
100 years of Daylight Saving
On the centenary of Daylight Saving in Britain, Curator of Horology, Rory McEvoy looks back at its history.
Longitude found - the story of Harrison's Clocks
Who was John Harrison, and how did his clocks help to solve the problem of finding longitude at sea?
Why 12 months in a year, seven days in a week or 60 minutes in an hour?
While days and years are (fairly) neat astronomical events, what explains months, weeks, hours and minutes?
Which time is it?
Next time someone asks you the time, you may enquire if they want to know the atomic, universal, civil, local, solar or sidereal time
The Greenwich Time Ball and one time for all
How do you know that your watch, clock or phone is telling exactly the right time? At one time, the only way was to look to the roof of the Observatory.
Sundials
For thousands of years, the sundial has told the time and divided the day.
Is noon 12 am or 12 pm?
Ever wondered whether midday or midnight is 12 am or 12 pm?