Zumanjaro: Drop of Doom is the theme park's newest ride.
It lifts riders 41 stories, then drops them straight down at 90 miles per hour in less than 10 seconds.
On Tuesday, crews put the last piece of steel at the top of the tower. They'll spend the next few weeks installing the lift equipment and ride controls.
Zumanjaro is expected to open for Memorial Day weekend. The park is scheduled to open Saturday, April 12, about a month and a half ahead of Zumanjaro.
Connected to the iconic Kingda Ka roller coaster, the 456-foot monster that ranks as the world's tallest coaster and fastest in North America, Zumanjaro will hoist riders 415 feet into the sky and rocket them back to Earth while Kingda Ka trains launch right toward them at speeds of up to 128 miles per hour.
"Zumanjaro solidifies Six Flags Great Adventure's dominance as the Northeast's thrill capital," park president John Fitzgerald said. "This is precisely the world-class, record-breaking attraction our guests have come to expect from Great Adventure. Zumanjaro is destined to top many must-ride lists in 2014."
Three soaring Zumanjaro towers have been built on the face of the massive Kingda Ka coaster debuting during the park's 41st season. Each drop tower will feature a gondola with eight riders.
The gondolas will rise to the top of the tower in approximately 30 seconds. Riders will pause for a few terrifying moments, higher than London's Big Ben and twice as high as the Statue of Liberty, allowing them to catch a glimpse of the skyscrapers in Philadelphia 52 miles to the south before gravity plunges them back to ground level.
Park officials also announced that the introduction of Zumanjaro spells the end of an era for one of the park's classic roller coasters, Rolling Thunder. The coaster, which opened in 1979, has delivered more than 42 million rides in its nearly 35-year history.