May Natural History Museum is an entomology museum in Rock Creek Park, Colorado. The museum describes its holdings as the world's largest private insect collection. The museum was founded by John May in 1952.

The May Museum consists of unique 7,000 specimens of insects and spiders housed in custom-made cases with handwritten labels. The collection includes a wide variety of insects including beetles, butterflies, centipedes, and more, from locations in South America, Africa, Asia, and elsewhere. Some specimens included in the museum's collections are now thought to be extinct.

The scale of the collection is impressive on its own, but at each case one is impressed as well by the remarkable quality and condition of its specimens, and above all, its variety.

The carefully-written labels indicate that the bugs were gathered from locations as far flung as Brazil, Indonesia, South Africa, and Papua New Guinea, and several varieties were discovered by May for the very first time. 

According to atlasobscura & wikipedia