You won’t find complete agreement on which waterpark was the first, but nearly everyone agrees who the “Father of the Waterpark” is: George Millay. Millay is a creative genius who came up with the idea of SeaWorld in 1964, which took the idea of sea-life parks to new levels. In 1977, he did the same to the amusement industry—changing it forever—when he opened the gates of Wet ‘n Wild in Orlando, Fla.

As biographer Tim O’Brien writes, Millay is “a man who turned water into gold—a modern-day Poseidon with the creativity, stamina and smarts to conceive recreational opportunities centered on the sea and oceans.”

In 2004, the World Waterpark Association honored Millay with a Lifetime Achievement Award, the first ever given by the Association. WWA also presented Millay an official proclamation naming him “Father of the Waterpark.”

After Wet ‘n Wild opened in 1977, other parks began springing up around the country. Huge, concrete slide structures were the norm back then. The industry became more focused in 1981 when the World Waterpark Association was formed. They brought together the wave pool from Europe, the leisure river and speed slide from the Asia-Pacific region of the world and the waterslide from California—among other remarkable innovations—to create what is known today as the waterpark industry.

Today, waterparks are being built at an astounding rate all over the world. They come in a multitude of shapes and sizes, from small aquatics centers that have a few waterpark features—such as a waterslide or leisure river—to city-owned facilities that rival some of today’s major parks, as well as indoor waterpark hotels/resorts. Growing number of other industries are also joining in the waterpark trend. Campgrounds, ski resorts, cruise ships… These are only a few of the recreational businesses recognizing the watery appeal of the waterpark.