Thor's Well is a natural salt water fountain made out of a gap in the intertidal rock, driven by the power of the ocean tide. The sea appears to "breathe" here, alternatingly inhaling the water, and then spouting it out with occasional ferocity. When photographed during the right phase of the tidal cycle (from an hour before to an hour after high tide), and at the precisely correct moment, it looks as if the water is draining out of the ocean through a hole! So, getting a sunset shot of Thor's Well in action like this requires planning your trip to the Well during a time of the month when the high tide happens to overlap with the sunset time. You see how creating a memorable photograph requires knowing and coordinating everything from astronomy, to geology, to meteorology and ecology.