Why was the Royal Observatory built?
Until the 18th century, sailors could only accurately measure their north-south position, or latitude. As a result, voyages were difficult and dangerous. Ships ran aground on rocks because navigators did not know their exact position, or ran out of food and water because journeys took longer than expected. Sailors needed to know their east-west position, or longitude, as well as their latitude, to plan and make safe journeys. In 1675, King Charles II ordered the building of an observatory at Greenwich to try to find a solution to this problem. The Royal Observatory was designed by Sir Christopher Wren. To save money it was built using second-hand bricks, and cost just over £500.
