Joseph Williamson made his fortune in the Liverpool trading and tobacco industry in the early 1800s. Around 1817, after the Napoleonic Wars, Liverpool was unexpectedly hit by a recession, fueled by unemployed soldiers returning from war and fading commerce.
Williamson, prosperous and retired, began an extensive construction project on his estate, carving tunnels out of the sandstone. It is unclear, though, what his real motive was in building these extensive tunnels. Speculation had it that he was part of an eschatological — the study and philosophy of the end days — cult and the tunnels were for his friends and family in the end times. But more likely, the tunnels were a charitable endeavor — he had them dug just to keep his workers employed. There are tales of Williamson instructing his workers to move a pile of bricks from one place to another, and back again, just to keep them busy.
However, following his death in 1840, the tunnel project halted, and they fell into disrepair. Water gathered underground, and neighbors dumped their rubbish into the buried caverns. As buildings were demolished, the rubble was stuffed in the tunnels by the city. (This may, actually, have saved some of the tunnels from falling in on themselves. As archeologists have removed the rubble, the tunnels have been found in good condition.)
The tunnels range in size from a huge hall — 70 feet long, 25 feet wide with 20 foot ceilings — to a narrow passage four feet wide and six feet high. It is still unknown how many tunnels there are and how far they reach, as excavations are still underway.
In 1989, the Joseph Williamson Society was founded. The Society encourages education and research about Joseph Williamson, and, specifically, the tunnels. They began the excavations and continue to fund the work. They are a charitable organization and rely on the funds generated by visitors.