A program on “Ohio’s Hidden Wonders” will be featured during an open house from 1 to 4 p.m. Sunday in the Discovery Center at Oakwoods Nature Preserve.

The free family program will feature fairy shrimp, crayfish and aquatic worms.

A video will be shown that features vernal pools, pictures and stories about what sorts of things have been found during hikes in the Hancock Park District system, and books to explore.

Registration is not necessary.

For more information, call the Hancock Park District office at 419-425-7275.