Almost three quarters of the Earth's surface are covered with oceans. Unfortunately, most of the marine environment remains, to date, unexplored by scientists, and little is known about the variety and the distribution of ocean species and about living processes characteristic of the marine ecosystem. One thing we do know, however, is that the oceans are a habitat for many marine organisms with highly promising applications in marine biotechnology and in marine biomedicine. Marine biomedicine is a rapidly growing research area investigating how marine products or their derivatives can be used in biomedical research or in the pharmaceutical industry. The seminar will briefly describe the scope of applications of marine organisms and of marine products in biomedicine. In particular, I will use one of my own research projects as an example to illustrate how sharks can help us to cure cancer. Using the same example, I will point out the importance of a strong knowledge of biochemistry, molecular biosciences, and marine biology in the protection and conservation of sharks, sponges, algae, and many other "treasures from the deep blue sea".