The white rhinos in Lake Nakuru National Park are usually placid and, with caution, it is usually possible to get quite close to them. My favourite method is to let them come to me, trying to guess where they are heading. On this occasion, it worked really well and the rhinos came within 5 metres of the car, which was quite unnerving. I wanted to take an eye shot and managed it.
Nikon D700, Sigma 150-500mm at 500mm, F 6.3, 1/1600s, ISO 640, handheld.
Lake Nakuru National Park, Kenya