http://www.slate.com/articles/video/video/2015/10/wave_lab_delta_flume_makes_largest_man_made_waves_in_the_world_video.html

The Dutch, no strangers to flooding, recently opened the world’s largest man-made wave facility to help research better preventative technology. The Delta Flume is huge: 984 feet long, 31 feet high, and 16 feet wide, it holds the equivalent of four Olympic swimming pools’ worth of water. It uses a hydraulic system to generate waves that can reach nearly 15 feet high.