THEY tackled some of the greatest challenges on earth, and now Royal Mail commemorates six incredible achievements which spanned the last century.

Extreme Endeavours, issued on Tuesday, allows designer Howard Brown to take a "panoramic" approach to conquests and achievements.

And the Shuttle/Times and News has 20 sets of first day cover stamps to give away in an easy to enter competition.

The stamps feature six major team and individual accomplishments. The issue also celebrates two anniversaries - the 50th anniversary of the conquest of Mount Everest, and the 100th anniversary of Amy Johnson's birth.

Amy Johnson appears on the second class stamp. Known as the Queen of the Skies, she was the first woman aviator to fly solo to Australia - a feat she achieved, after just 50 hours' flying experience, in 1930.

The first class stamp features the British team's conquest of Mount Everest. This feat was achieved by Sir Edmund Hillary and Tenzing Norgay.

The other end of the temperature scale is reached on the E class stamp, which features Dame Freya Stark who travelled into remote areas of Iraq, Iran and Saudi Arabia.

Polar hero Sir Ernest Shackleton features on the 42p stamp. The 47p stamp celebrates Sir Frances Chichester sailing solo around the world in 1967. Captain Robert Falcon Scott, better known as "Scott of the Antarctic", features on the 68p stamp.

To enter the competition, simply answer one question:

who was known as the Queen of the Skies?

Closing date: Friday, May 16.

Normal Newsquest rules apply.