It all began when L.M. Mann bought 100 acres of land and created a destination. He opened the Des Moines Zoological Gardens on July 4, 1889. The park included an elephant, lions, panthers, kangaroos, monkeys, elk, numerous birds, and other animals. Mann ran the zoo for one year and then sold it to numerous business men who made improvements, including a levy on the south side of the park.
In 1912, local businessmen became interested in creating an amusement park in Des Moines. The Zoological Gardens were no longer in use and became the chosen property for Riverview Amusement Park. An ice company owned the property and had been harvesting ice from the Zoo Lakes. Ice makers were now in use, so the lakes were no longer needed for gathering ice.
From 1915-1978 the location was the Riverview Amusement Park, and is now Riverview Park.
The Des Moines Mail & Times had high praise for Mann and published this in their Souvenir of Des Moines.
The opening of the Zoological Gardens to the citizens of Des Moines marked the first effort put forth to provide a recreation ground for the inhabitants since the city was founded. It not only required nerve, but capital, to start the enterprise, and it took just such an indefatigable worker, sagacious capitalist and far-sighted citizen as Mr. L. M. Mann to put the plan into execution. After expending a large sum in grading up the grounds, hollowing out the artificial lake, a mile in extent, building a tight fence around the whole acreage, and for divers minor improvements, Mr. Mann took the train and went to Boston, where he secured the whole collection of wild animals in a bunch from an institution that was going out of business, and wrote his check for over $5,000 in payment for them. The shipping of such an aggregation was quite an item, and an expert was employed to bring them out here and take charge of them after they arrived... The results of this outlay of capital have been quite satisfactory. Mr. Mann in all his speculations has quietly endeavored, while promoting his personal interests, to instill into his undertakings a spirit of broad philanthropy. It forms one of the prettiest sights to be seen anywhere, to witness the crowds of well dressed, happy faced people gathered beneath the shades of the umbrageous foliage on almost any day in the week, and especially on Sunday, breathing the pure, fresh air, and listening to the strains of music as they float upon the ambient air.