The Valley of Adventure (published in 1947) is a popular children's book by Enid Blyton.

When Bill gets a new plane, the children (Phillip, Dinah, Jack and Lucy-Anne) are allowed to go on a night flight to the countryside to spend a short holiday studying nature.

But the children accidentally board the wrong plane, and find themselves being flown by two men, Juan and Pepi.

Meanwhile Jack discovers a prisoner named Otto who gives him a mysterious map that leads to a treasure, hidden somewhere in the valley.

The children after many days of scrambling and climbing rocks, discover a cave with priceless statues taken throughout the country during the war.