The expedition of Meriwether Lewis and William Clark in 1804-06 is one of the most famous episodes in American history. They might never have reached the west coast had a young Shoshone woman and her baby not been with them. Read our special Christmas feature (one of several in our holiday double issue) to find out why.

A chapter of British history will close next year, with the banishment of hereditary peers from the House of Lords. But what makes an aristocrat these days? We investigate.