Unexplained Mysteries across the United States

General Chicago Englewood area of Holmes’s former mixed-use building later sensationalized as the “Murder Castle.” The original structure is gone.

Public museum anchor for documented local history of Belle Gunness and the 1908 La Porte farm investigation, avoiding a private former-farm destination.

Village-level reference for the 1957 Ed Gein investigation near Plainfield. The former farm is intentionally not mapped as a visitor destination.

1668 Turner-Ingersoll Mansion that inspired Nathaniel Hawthorne’s 1851 novel and later became a preservation and settlement-house nonprofit.

Preserved Denver home associated with Margaret Tobin Brown, Titanic survivor, activist and philanthropist.

Historic Tombstone cemetery with burials from the mining-town era and later Wild West folklore.

Historic Baltimore burial ground established in 1786, containing Edgar Allan Poe’s grave and a church built over older graves.

Broad site reference for Operation Cue and the May 5, 1955 Apple-2 atomic test. Exact test-house coordinates are intentionally not exposed.

Public museum and inn at the Fall River house where Andrew and Abby Borden were murdered on August 4, 1892. Lizzie Borden was tried and acquitted.

General Lower Rouge River area of the former Michigan Carbon Works, where the famous 1892 bison-skull pile was photographed.

City-level reference for the May 1, 1936 FBI arrest of Alvin Karpis in New Orleans.

City-level historical reference for the 1991 arrest and investigation of Jeffrey Dahmer. The former apartment site is intentionally not used as a tourism pin.

City-level reference for the Wichita-area BTK murders and 2005 arrest of Dennis Rader. No victim residence or private crime scene is mapped.

General Chicago-area reference for the Chalifoux family photograph published in August 1948. The original private yard is not mapped.

Sand Cave is a documented cave. It is on OK MAP because ODDKNOWN also catalogs unusual natural locations and underground features. This record comes from OpenStreetMap via Strange Places; th

Dewdrop Cave is a documented cave. It is on OK MAP because ODDKNOWN also catalogs unusual natural locations and underground features. This record comes from OpenStreetMap via Strange Places;

Sand Cave is a documented cave. It is on OK MAP because ODDKNOWN also catalogs unusual natural locations and underground features. This record comes from OpenStreetMap via Strange Places; th

Potter Branch Double Arch is a documented cave. It is on OK MAP because ODDKNOWN also catalogs unusual natural locations and underground features. This record comes from OpenStreetMap via St

Violet City Entrance is a documented cave. It is on OK MAP because ODDKNOWN also catalogs unusual natural locations and underground features. This record comes from OpenStreetMap via Strange

Forestiere Underground Gardens is on OK MAP because Baldassare Forestiere spent decades carving an underground home, tunnels, rooms, courtyards and gardens beneath Fresno's hardpan. Fresno C

Amargosa Opera House is on OK MAP for the documented story of dancer Marta Becket, who settled at isolated Death Valley Junction and transformed a former social hall into a theater where she

The Noah Purifoy Desert Art Museum is on OK MAP for its ten-acre outdoor landscape of large assemblage works built from discarded and weathered materials. Purifoy spent years creating the Jo

Galleta Meadows is on OK MAP for the enormous metal creatures scattered across the desert around Borrego Springs. Visit California describes roughly 130 Ricardo Breceda sculptures, including

Desert View Tower is on OK MAP as a documented 1923 stone landmark above the In-Ko-Pah Mountains, paired with the maze-like Boulder Park Mystery Caves and their hand-carved folk-art figures.

Pioneertown is on OK MAP because what looks like an old frontier settlement was actually created in 1946 as both a functioning community and an Old West movie set. Visit California documents

The former Pike amusement zone is on OK MAP because of one of Long Beach's strangest documented stories. During filming in the 1970s, a hanging 'mannequin' in an attraction broke apart and w

Barker Ranch is on OK MAP because the remote Death Valley property became a hideout for Charles Manson and members of the Manson Family in 1968–1969. National Park Service history records th

A small percentage of residents around Taos have reported hearing a persistent low-frequency hum that others cannot hear. Similar 'hum' reports occur in several places around the world.