Steel is the skeleton of the structure, and the rebar will be handled by dozens of the 1,000 men and women working the tower. Pat Foye, executive director of the Port Authority of New York and New Jersey, which oversees the site, pulls up yesterday's steel report on his BlackBerry. "We installed 121 pieces, welded the 104th-floor column splices, spread steel decking on the 105th floor, and lost nothing to weather." Meaning? "If it's raining or winds are above 30 miles, we've got to stop." Yesterday was hot and hazy; today is the same. Work isn't stopping, so let's follow that rebar.

From 1,200 feet the city sounds like a dull drone. Tom Gordon leans out in his seat and stares down, like a fisherman attempting to glimpse his bait. He's looking at the bundle of steel far below. Gordon operates a slide crane on the 91st story -- though, as the name suggests, the crane slides up as the tower gets built. The building topped out last week, so in a few months Gordon's crane will come down, piece by piece, carried by another crane on the roof. For now, his operating cabin in the slide crane on the north face of 1 World Trade is the ultimate corner office.

Gordon laughs at that notion and admits as much. It's quiet up here once the thrum of the 500-horsepower diesel fades to the background. The rebar, like other heavy loads, isn't as tricky to lift as the lighter stuff, like window panes, which catch the wind. Gordon's got maybe 20 feet for error, not much when considering there are thousands of pounds attached to a 900-pound ball attached to 1,000 feet of cable moving up and over toward the tower and the platform on the 93rd floor where concrete workers are waiting for it.

Gordon goes silent while the crane slowly turns clockwise, the rebar rising across the horizon line, approaching the building. It's an eerie image for a moment, the bundle of steel moving toward the tower. Ken Klemens, a master mechanic standing outside Gordon's cabin, says the memory of the tragedy that preceded this place is inescapable, even 1,200 feet up. "This is the best job we never wanted," he says.

Inside Tom Gordon's slide crane on the 91st story of 1 World Trade Center. Gordon has been a crane operator for nine years. His day starts at dawn. To enter his "office" at the crane's controls, he climbs two ladders off the side of the tower.

The slide crane, seen hanging over the north side of 1 World Trade Center, is only used to build extremely tall skyscrapers. Its unique design allows the crane to move up as the tower is built.

Crane operator Danny Dunn watches the sun rise over Manhattan. His crane, atop the tower, is about six stories higher than the roof of the building. When the slide crane comes down in a few months, the cranes on top will carry it.