I know that the answer to the question "What happened later, Edward Whymper reaching the top of the Matterhorn or the first ascent of the Eiger Nordwand?" is in "The first British Mont Blanc ascent was in 1788; the first female ascent in 1819. By the mid-1850s Swiss mountaineers had ascended most of the peaks and were eagerly sought as mountain guides. Edward Whymper reached the top of the Matterhorn in 1865 (after seven attempts), and in 1938 the last of the six great north faces of the Alps was climbed with the first ascent of the Eiger Nordwand (north face of the Eiger).". Can you tell me what it is?
A:
first ascent of the Eiger Nordwand