Born into abject poverty and raised in the slums of New York City, Mackay became one of the four Bonanza Kings, a partnership which capitalized on the wealth generated by the silver mines at the Comstock Lode in Nevada, making him one of the richest Americans in his time.

He also headed a telegraph business that laid transatlantic cables, and he helped finance the New York, Texas and Mexican Railway Company.

As a boy Mackay hawked newspapers such as the New York Herald, and later apprenticed at William H. Webb Shipyard to support his mother and sister.

[2] In 1851, he sailed by clipper around the Horn to California and worked eight years in placer gold fields in Sierra County without much success.

In 1865 he used his savings to buy into the Kentuck[3] mine and hit big, he was suddenly worth US$1.6 million, more than enough to retire for life.

In 1873, the Con Virginia made the greatest ore body discovery ever found in North America, known as the "Big Bonanza".

"Louise" was born in New York and moved to the Downieville, CA goldfields with her parents, Major Daniel E. Hungerford and his wife Eveline, in 1854.

[7] Shortly after, in 1864, Dr Bryant left his wife and only living daughter in Virginia City, without funds, a fate close to abandonment.

Mrs. Bryant was kept out of prostitution only with the help of a benevolent father Patrick Manogue, who found her work sewing dresses for the "well-to-do" ladies of the camp.

Sometime in early 1866, Mrs. Bryant found out her husband was sick and dying of tetanus in a mining camp northwest of Downieville CA.

He purchased a large mansion for her in Paris, 9 Rue de Tilsit, where his wealth enabled her to become a noted society hostess for two decades, entertaining royalty and throwing lavish parties.

[13] As his telegraph business expanded, in 1884 the family was moved to London for the boys' schooling and easier communications through his owned cables.

[15][16] In 1884, with James Gordon Bennett, Jr., Mackay formed the Commercial Cable Company, largely to fight Jay Gould and the Western Union Telegraph Company, laid two transatlantic cables, and forced the toll-rate for transatlantic messages down to twenty-five cents a word.

ITT organized the Postal Telegraph & Cable Corporation as a shell to acquire and control the Mackay System on May 18, 1928.

[18] Though plagued with financial troubles during the Great Depression, the Mackay System continued to be the chief rival of Western Union until 1943.

A Texas corporation was formed to take advantage of the state's generous land grants and build a railroad from Richmond to Brownsville.

[19] In addition to the Bank of Nevada and the communications companies, Mackay held interests in mines in Colorado, Idaho, and Alaska and timber lands and ranches in California.

In June 1908 the Mackay School of Mines building was presented to the University of Nevada, as a memorial to him, by his widow and his son, Clarence H.

[21] The mausoleum was originally created for Mackay's oldest son, John, Jr., who died in a horse riding accident in 1895.