Greenwich Park and the Royal Observatory




2.75 miles (4.4kms)

154ft (47m)
1hr 15min

About the walk

Marcus Aurelius Antoninus once said 'Time is like a river made up of the events which sooner does anything appear than it is swept away, and another comes in its place'. Many centuries later, these words could have applied to the problems encountered at sea by captains and their crews where, over and over again, ships were wrecked because of a lack of navigational aids. Until the 17th century, captains could tell the ship's position of latitude by the stars and the sun, but longitude was a real problem: they had no way of telling how far east or west a ship was positioned.

A formidable task

It was Charles II who rescued Greenwich after it fell on hard times under Oliver Cromwell. Previously the birthplace of Henry VIII and his daughters Mary I and Elizabeth I, Greenwich was given a Royal Observatory in 1675 to try to provide seafarers with more accurate charts. The first Astronomer Royal was John Flamsteed who took the job at the age of 28. During his 45 years at the observatory, he made more than 50,000 observations. There was just one problem – in this time he had not arrived at a solution for longitude. The last straw for the government came in 1707 when four Royal Navy ships sunk off the Isles of Scilly, claiming 2,000 lives. Parliament offered a reward of £20,000 for anyone finding a solution to the longitude problem. It was eventually claimed – by a clockmaker.

John Harrison (1693-1776) came down to London in 1730 with the idea that longitude could be worked out by using the time. His solution was based on the fact that for every 15 degrees travelled eastwards, the local time moves one hour ahead. Therefore, if we know the local times at two points on Earth, we can use the difference between them to calculate how far apart those places are in longitude, east or west. This idea was crucial to sailors in the 17th century. The problem was that every minute gained or lost could consequently amount to a navigational error of 15 nautical miles (17.25 miles or 27.8km) so the solution hinged on producing a clock that kept the exact time in turbulent conditions. Harrison made four clocks for this purpose. The first was designed to run consistently, regardless of movement or temperature changes. He made a second clock, then took 19 years to work on the third prototype, the H3. However, it was his fourth, the H4, which clinched the deal. The most compact, it was the forerunner of all precision watches and provided the basis for an accurate sea chronometer that finally enabled sailors to work out their exact position. Ironically, Harrison was well into his seventies before he received any prize money. Despite the success of his machines, the committee responsible for paying him stalled repeatedly and only the intervention of King George III secured him recognition and his just reward.

In 1884 it was decided, at an international conference in Washington DC, that Greenwich should become the site of the prime meridian, an imaginary line running north to south, denoting the world's longitudinal zero. This means that every position on Earth is defined by its longitude (distance east or west) from Greenwich. With a little help from Charles II and Flamsteed, John Harrison left the world a timeless legacy.

Walk directions

With the Cutty Sark on your left (the ship was restored at a cost of £50 million after a fire in 2007), cross the road ahead into Greenwich Church Street. After a further 70yds (64m) turn left into the market. At the far end turn left (by Stewart John shop), then right, and follow King William Walk to Greenwich Park.

Enter the park at St Mary's Gate and follow the widest path (signposted to the Café, Flower Garden and Old Royal Observatory), as it swings to the left. Continue ahead, turning right to reach the Royal Observatory and a superb view over London and Greenwich Royal Naval College.

Continue past the Royal Observatory's Peter Harrison Planetarium building and the Pavilion Teahouse to follow this broad pathway, Blackheath Avenue. Just before Blackheath Gate turn left through metal gates on to the Flower Garden path, which skirts the edge of a large pond. (A tiny path a few paces on to the right leads into an area for viewing the deer.)

Turn right at the next fork and go through the gates. Turn left and take the right-hand fork beside a wall. Continue along this straight path.

At the next junction take the second path on the left and then take the signposted Queen Elizabeth Oak path. Keep ahead, straight over another set of paths, to reach another junction at which the remains of a fallen oak tree are protected by railings. This dates from the 12th century and lived to a ripe old age of 700 years. It is said that Anne Boleyn danced around the tree with Henry VIII, and their daughter, Elizabeth, would often play in the hollow trunk of the huge oak.

Keep going downhill and right at the next junction on a path that dips and rises. Continue ahead at the next set of paths and leave the park with the National Maritime Museum on your left. Go straight ahead at Park Row Gate across Romney Road.

At the Trafalgar Tavern turn left along the Thames Path to reach the Cutty Sark site and the start of the walk.

Additional information

Tarmac paths

Parkland and superb views across London

On lead in foot tunnel

OS Explorer 161 London South

Greenwich Park and Pier

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About the area

Discover Greater London

Greater London is one of the world’s largest urban areas; 33 boroughs stretching north to Enfield, south to Croydon, east to Havering, west to Hillingdon and with central London at the heart of it all.

Greater London was officially created in 1965, but the boroughs themselves all have their own histories going back much further. Greenwich is home to the Prime Meridian, which all clocks on earth take their time from, while Hounslow contains Heathrow Airport, one of the busiest airports in the world. Greater London contains a multitude of parks and green spaces, from the six Royal Parks (including Richmond Park, Green Park, Hyde Park and Regent’s Park) and other huge open spaces like Hampstead Heath and Clapham Common; to smaller community spaces like Clissold Park in Stoke Newington and Burgess Park in Southwark.

The centre of London has its quiet spaces too, like Coram’s Field by Great Ormond Street, and Camley Street Natural Park, a stone’s throw from King’s Cross and St Pancras. One of the city’s most impressive features is the London Underground. Beginning in 1863 as the Metropolitan Railway, it took commuters into The City from the suburbs of Middlesex. It was the first underground railway in the world, and now consists of 11 lines, 270 stations, and 250 miles (402km) of track. It’s estimated that nearly five million journeys are taken every day, and there are nearly one and a half billion riders each year.  At peak times, there are more than 543 trains whizzing around the Capital.