It is called K Street: a line of sparkling office blocks and fancy restaurants north of the White House. It is the heart of the lobbying industry in Washington DC, servicing clients and politicians from all over the US and one of the most powerful stretches of tarmac in the world.
It also might be one of the most corrupt: how corrupt was revealed last week when a scandal exploded exposing the ugly role of lobbying in US politics and threatening to bring down some of the biggest names in public life.
The man at the center is Jack Abramoff, Washington's lobbyist extraordinaire, who pleaded guilty last week to criminal charges and fleecing his clients. The plea means he will be naming names in an influence-peddling scandal that runs all the way to the White House.
Abramoff was employed by wealthy Native American tribes who ran reservation casinos. He was supposed to lobby politicians on their behalf, but instead stole millions of dollars from them. Now the case has put a rare spotlight on the entire lobbying system and some of the most powerful men in Washington are running for cover. They stretch from President George W. Bush himself, to top Republican officials, to the heads of thinktanks, to senior congressmen from both parties.
Abramoff represents how much of Washington works. That system is fuelled by two things: money and lobbyists.
There are believed to be more than 30,000 lobbyists in Washington, outnumbering elected federal politicians by almost 60 to one. The money they deal in tops US$2 billion a year. The US constitution is often praised for its checks and balances between the president, Congress and the Supreme Court. But where money equals power, no one predicted the unofficial fourth branch of US government: K Street.
Few politicians escape the lobbyists' influence. Both Bush and Democratic challenger John Kerry spent around US$250 million each fighting last year's presidential race. But the figures lower down the political ladder are huge too. One study estimated the average senator in Washington needs to spend about US$20 million to defend a seat successfully. Politicians need money and only corporations and wealthy individuals can provide it. Between 1998 and 2004 lobbyists spent US$13 billion to promote their clients' desires.
Watchdogs have revealed how lobbyists have positioned themselves as organizers for politicians' fundraising efforts. An investigation by the Center for Public Integrity anti-lobbying group found lobbyists were treasurers for 800 "political action committees" which funnel funding to politicians to help them get elected.
It also found lobbyists were treasurers of 68 politicians' campaign committees, which had raised US$500 million since 1998.
At the heart of Washington's lobbying industry is the "revolving door": lobbyists take up powerful positions in government at the same time as politicians end their careers by getting lobbying jobs to cash in on their political contacts.
Some of the highest officials in the White House are former lobbyists. Andy Card, one of Bush's most trusted advisors and the President's chief of staff, is a former lobbyist for the car industry. In all, 12 ex-lobbyists work in the White House. Going the other way, federal officials and politicians head to K Street.
Since 1998 more than 2,200 former federal employees have become lobbyists, including 273 former White House staffers and 250 ex- members of Congress or heads of government departments.