The house that Tweed built: A symbol of municipal corruption.

The Old New York County Courthouse-"Tweed Courthouse"  ,  located on the north side of City Hall Park, behind City Hall, on Chambers Street, is one of New York’s greatest civic monuments. The Courthouse was built  between 1861 and 1881 and is the costliest public building that had yet been built in the United States. Its construction cost nearly twice as much as the purchase of Alaska in 1867.
Tweed Courthouse is known as the  greatest single thievery project of  'Boss Twed'.  You cannot understand New York without understanding its most corrupt politician -- William 'Boss' Tweed  (1823-1878),     who led a group of corrupt politicians who gained power in the Democratic party in 1863.    Tweed started working at a brush factory, and moved into management after marrying the owner's daughter.
 By the late 1850s Tweed and his associates controlled the group, and in 1863 he was elected Chair of Tammany Hall, the behind-the-scenes group that had make-or-break power over local Democratic Party nominations. "Boss Tweed" was himself appointed a Deputy Street Commissioner, and began putting cronies on the city payroll for doing no work.
Tweed bought several companies which were promptly awarded city contracts. He was elected to the State Senate in 1867, and within months had charmed and cajoled his way to similar near-absolute control over the state's capitol.
It has been estimated that during his reign of corruption, William Magear Tweed, the “Tiger of Tammany,” and his political cronies stole $200 million (the equivalent of about $3.5 billion in today’s money) from the citizens of New York. 

In an era in which all of the land for Central Park cost New York City $5 million, and the elaborate St. Patrick’s Cathedral cost $2 million to build, the Tweed Courthouse wound up costing New York’s taxpayers $12 million (equivalent to about $200 million today). The Tweed courthouse was not completed until 1880, two decades after ground was broken. By then, the courthouse had become a symbol of public corruption. "The whole atmosphere is corrupt," said a reformer from the time. "You look up at its ceilings and find gaudy decorations; you wonder which is the greatest, the vulgarity or the corruptness of the place."

Building bills were wildly inflated in order to provide generous sums for kickbacks. Enough carpet was ordered to cover all of City Hall Park three times, and many of the companies billing for carpeting did not even exist. The final costs for brooms for the courthouse, $250,000, matched the total originally budgeted for the entire building!

The immediate cause of Tweed's downfall was the publication in the New York Times of evidence of wholesale graft revealed by M. J. O'Rourke, a new county bookkeeper. In famously barbed caricatures, Thomas Nast, cartoonist for Harper's Weekly, was one of the few prominent voices to speak against Tweed.

Tweed was tried for felony, but the jury could not reach a verdict. In a second trial he was convicted and given a 12-year prison sentence; this, however, was reduced by a higher court, and he served one year.He was arrested once more on other charges, but escaped from the prison    and   fled to Cuba, then Spain. In Spain   he was recognized from Nast's political cartoons and was turned over to an American warship which delivered him to the authorities. Tweed died in prison two years later.
In his biography of Tweed, Kenneth Ackerman wrote:

"William Tweed had left enormous footprints on his city; he had built as grandly as he’d stolen. His monuments dotted every corner of Manhattan – the new Brooklyn Bridge rising across the East River, the opulent new County Courthouse by City Hall, the widened, paved streets up Broadway and around Central Park. Just as striking were shadows of his huge crimes- the huge debt and ruined credit that would haunt city finances for a generation, the broken lives and shattered trust of former friends. Tweed had defined a grimy reality of American politics, perfecting forms of graft and voting-box abuse mimicked by political bosses for the next century, but never on so grand a scale. His fall had created a new role for a free, skeptical press in the public arena, and his legal persecution had set a tone for political scandals lasting generations."
 
In the spring of 1999 Tweed house was restored.  Archaeologists from Hartgen Archeological Associates, Inc., hired to test for archaeological resources during the restoration,  found 23 intact skeletons, mostly in front of the building and just inches below the sidewalk. 

The restoration  firm carefully removed as much as 18 layers of paint to reveal the original brick walls and cast iron in order to recreate the original paint colors.   The Guide to New York City Landmarks characterizes the building as containing "some of the finest mid-19th century interiors in New York." 
Today the building serves as the headquarters of the Department of Education. Tours of Tweed Courthouse are offered by reservation on select Fridays at 12:00 PM.