The five-year saga involving the General Services Administration and 1 World Trade Center reflects both intractable Washington gridlock and the lurching progress at the building formerly known as the Freedom Tower.

When the GSA , an independent government agency in charge of supplying and managing federal offices, secured a 270,000-square-foot lease at 1 World Trade Center, it pushed the still-rising landmark above 50 percent occupancy.

But along the way there was a dramatic scaling back of lease terms, an angry congressman and a Las Vegas spending spree that nearly torpedoed the transaction.

After the jump, an illustrated guide to the biggest deal of the year. Read More