The wake of the ferry to Mackinac Island, Michigan, whipped into
whitecaps by a stiff breeze blowing through the Mackinac Straits. The
full photo also showed the horizon and part of the Mackinac Bridge,
but I think cropping to focus on the waves makes for a better picture.

5:42pm EST, October 5th 2004
1/727sec, f8.2, ISO 100, focal length 31.0mm
Cropped, resampled.