original article found here:
It is a hoax...but interesting.
Chicago and the Cardiff Giant
The Cardiff Giant, the 10 foot "petrified giant" dug up in Cardiff, New York in 1869, has been called one of history's greatest hoaxes - a statue that fooled the world. In fact, it doesn't seem to have fooled very many people. When George Hull, a Cardiff farmer, announced that he had found the petrified giant while digging for a well on his farm, it attracted plenty of attention, but geologists knew that there was no good reason to dig a well where he was digging, and sculptors recognized the chisel marks. Even the most optimistic scientists merely called it an "ancient statue." Still, various preachers announced that it was proof that a line in Genesis about giants who once walked the Earth was true, and that therefore the entire Bible was true. The giant immediately became a huge attraction, and P.T. Barnum rushed to produce his own (and to call the one dug up in NEw York a fake).
Burkhart carved the giant in a barn which a 1985 Chicago Tribune article states was at 940 N. Clark. They don't say whether that was the address before or after the 1909 street renumbering, but I suspect it's the current address. In 1866 940 N Clark would be roughly where Clark and Fullerton is now - further North than most people lived then, and right in the middle of City Cemetery (which would have been fairly convenient, since Burkhart's work was mainly for cemeteries). 940 N. Clark on the current grid is right across the street from Washington Square Park (alias Bughouse Square). Either way, the barn is long gone now. If it was at the current 940 N, it would have burned up in the Great Fire. It might've been safer near Clark and Fullerton, but the only barn around there now is in the petting zoo at Lincoln Park.
Today, the giant is still on display at Cooperstown, NY (though it spent a good chunk of the 20th century in an Iowa rumpus room). One of the copies is near Fort Dodge, Iowa. Barnum's own replica is on display at a museum in Detroit. I think it's high time Chicago got its own version. It'd be interesting to find out if any of the angels Burkhart made are still in cemeteries - many were probably for City Cemetery (which is now Lincoln Park). He died shortly after the carving, and his family doubted that he knew that it was intended for use as a hoax (though I don't really see how he couldn't have).
Here's some info about Burkhart from his descendents
Museum of Hoaxes Entry on the Cardiff Giant