When President McAleese visited Butte, Montana this week, she appears to have missed out on the city's most famous feature, even though it's right in the middle of town. The Berkeley Pit is one of the world's grimmer tourist attractions, to be sure. But the people of Butte have made a point of embracing their history, warts and all, and they've gone to the trouble of providing a special platform from which tourists may view the most poisoned lake in America.
Reddish-brown, 1,800 feet deep, and rising, the waters of the Berkeley Pit are the apocalyptic vestige of a century of copper-mining in what was once "the richest hill on earth". Laced with arsenic and a cocktail of toxic metals, the lake has the acidity level of vinegar. When a flock of migrating geese landed on it some years ago, they died. Yet life survives even here. An insect called the Water Boatman has made its home in the pit, along with some types of algae that appear to thrive on iron.
The pit is in the middle of town because it used to be the town. In 1955, when falling copper prices meant tunnelling was no longer viable, the all-powerful Anaconda Mining company decided that open-pit operations were the future. Having little choice, the people of Butte (the word rhymes with "cute") sacrificed their oldest neighbourhoods, including Dublin Gulch. As ravenous as the name suggests, the Anaconda company had finally got around to eating its own city.
By then, central Butte was already the most undermined stretch of land on the planet. A hundred separate main-shafts had been sunk into the hill - one a mile deep - and then extended horizontally in all directions. Nobody knows the full extent of the tunnelling, although the estimate is somewhere between 7,000 and 10,000 miles. At the height of the copper frenzy, rival tunnels ran into each other, and hand-to-hand combat was not unknown.
With only a handful of grand buildings hinting at the powerhouse it once was, central Butte - where most streets are named after metal or rock types - feels a bit like a ghost town these days. The most visible ghosts are the surviving "gallows frames", still standing guard over their long-closed shafts, and now illuminated at night. But the craving for copper condemned 2,500 local men to underground deaths over the years, so there may be a few other ghosts lurking in the city's sometimes eerie quiet.
In any case it's hard now to imagine Butte as the thriving, rumbustious place that once drew tens of thousands of Irish emigrants, my grandfather and two of his sisters among them. In its heyday, the city's wildness was legendary, with more than 300 bars open 24 hours a day, seven days a week. In 1905, its red-light district was reputedly the second largest in the US, employing 1,000 women (very few of them Irish, it has been noted). A young Charlie Chaplin, one of many stars who played Butte, was so impressed with the beauty of the local prostitutes that he mentioned it in his autobiography.
With so much money in copper, Butte's corruption was legendary too. Two of the city's "copper kings" - William Clark and Cavan-born Marcus Daly - between them so completely owned the state legislature that the third (F. Augustus Heinze) had no option but to invest in the judiciary, which found in his favour in many disputes. But Butte was also "the Gibraltar of [ trade] unionism", a red enclave in which radicalism vied with the innate conservatism of the Irish poor. Miners were well paid as a result, although their working lives - and often their retirements - were short.
Many never reached retirement. Butte's most moving sight is the Granite Mountain Overlook, a memorial to 168 miners who perished in a catastrophic fire in 1917. Some of the victims did not die quickly, and the monument includes extracts from letters to loved ones, written as they waited for the end in tombs half a mile below ground. Their stoicism is astonishing. One man advised his wife to sell up and move to California. Manus Duggan, a 25-year-old foreman whose last notes were apparently written in pitch dark, assured his wife that he had no fear. "I ask forgiveness for any suffering or pain I have ever caused," he wrote.
Butte's human history was the bedrock that remained even after they cratered the town's heart. And for all its environmental problems, it is still a gritty, fascinating place. The "black heart" of Montana, it has embraced its past to such an extent that some of the less toxic waste piles are now preserved. Industrial pollution has become the spur for new technologies. And terrible as it is, the Berkeley Pit acts as a sump that keeps the surrounding water table safe, while the city struggles with the epic clean-up.
The population has stabilised at 35,000, barely a third of what it once was. Most now live in the new town, down on the flats. But the old town survives despite everything, and may yet thrive again. I'm assured of this by my cousin Rosie, a woman fiercely proud both of Butte and of the Ireland she has never seen, who still lives there, on a street called Granite.