Charles Darwin's sextant on show

Adventurers Edmund Hillary, Thor Heyerdahl, Chris Bonington and Richard Burton have all returned to Kensington to recount their expeditions and left behind souvenirs for the society.

Now the �6m Unlocking the Archives project, part-funded by a �4.5m lottery grant, means the public will also be able to view the archives.

The headquarters in Kensington, west London, opened in 1830 and has been visited by scholars and explorers from across the world.

The society will also get an education centre, a reading room and a new public entrance under the project.

It is estimated there are more than two million maps, photographs, books and charts within its archive.

A spokesman for the society called the archives "some of the greatest annals of scientific exploration and discovery in the world".

He said: "They illuminate not only the history and development of geographical knowledge, but also hold within them exceptional and valuable material on the shared cultural histories of modern Britain."