Biological physics is the exploration of biological systems by physicists. The goal is to find general concepts and principles. Stan Ulam, a famous mathematician, once said to me: "Ask not what physics can to for biology, but what biology can do for physics." The challenge comes not only from the complexity of even "simple" biological system, but also from the fact that biological physics interacts with biology, chemistry, computing, and mathematics. Myoglobin, the protein that stores dioxygen in muscles, is the hydrogen atom of biological physics. Myoglobin and hemoglobin were the first proteins whose structures were determined by Kendrew and Perutz. Their X-ray structures convey the impression that each atom is in its own place. But how could they function with just one conformation? Indeed, low temperature experiments that we performed a long time ago proved that a protein can assume many conformations and that function is based on motions from one conformation to another. Another surprise came from examining what controls the motions. A protein is surround by a hydration shell, one or two layers of water. Fluctuations in the shell control internal motions. Two techniques prove this fact. The fluctuations in the hydration shell are measured with dielectric spectroscopy; the internal motions are measured with the Mössbauer effect. Surprisingly, the Mössbauer effect in proteins displays two unexpected features, an apparent dynamic transitions and a broad line. A new look shows that both features are two sides of the same phenomenon; they are caused by the fluctuations in the hydration shell. Similar to the two-slit experiment, they involve the Heisenberg uncertainty principle and cannot be explained classically What are the concepts that have emerged so far? Possibly the most important one is the hierarchically organized free energy landscape. A second one is the role of environmental fluctuations in controlling protein dynamics. 50 years ago myoglobin was "fully understood". Now we know that we still have a long way to go even for this "simple" protein. And, remember, most biologic phenomena are much more complex.