This beautiful structure is to be found on the grounds of the Cincinnati Zoo and Botanical Gardens. A plaque mounted on the stone beneath the sculpture in the foreground reads as follows:
This memorial, sponsored by the Langdon Club, is dedicated to "Martha" September 1, 1914, the last passenger pigeon and "Inca" February 21, 1918 the last known Carolina paraquet and all extinct species. This building was home to "Martha" and "Inca" for many years until their deaths. It is the hope of the Langdon Club that people who visit this memorial will work toward the preservation of all of the world's fauna.
Notes: The Langdon Club was named in honor of Dr. Frank W. Langdon, an early Cincinnati neurosurgeon and naturalist. The bronze statue atop the plaque-bearing stone is of Martha, commissioned as a part of the monument. Martha lived at the zoo (where she was hatched) for about 29 years before her death.
PhotonStopper 
Wow.
(I'm lame…I didn't even know about that memorial, and I live 20 minutes away!)
Aint it the truth! Sometimes it's the "tourist-types" that find things of interest right under our noses! The zoo and botanical gardens is a beautiful place. I'll want to visit again some day when, hopefully, it's cooler. And I hope the city puts up better and bigger signs to help us out-of-towners find the zoo. — JG
What a fascinating memorial!