This chapter analyses how throughout the long twentieth century people strived to protect the Alps. After 1900, individual critics of mass tourism were joined by the nascent nature conservation movement, which perceived the rapid growth of Alpine tourism as a threat to both the culture and nature of the Alps. The following decades saw the birth of international conservation organizations, the creation of new protected areas, and the introduction of national laws and international conventions on species protection, but also substantial growth in Alpine tourism and the rapidly expanding exploitation of Alpine waters for electricity generation. From the 1980 onwards, Alpine conservation was increasingly informed and inspired by the environmental movement and triggered by controversies surrounding the construction of large-scale road infrastructure for transit traffic across the Alps. As this chapter shows, all these developments had distinctly European dimensions.