By CBS3 Staff

BETHLEHEM, Pa. (CBS) – Martin Tower is gone. Dynamite brought down the former world headquarters of Bethlehem Steel at 7:03 a.m. Sunday. The implosion rocked parts of the Lehigh Valley, those who say it was louder than they thought it would be and that you felt it in your feet.

It took just 15 seconds for the iconic 21-story Martin Tower on 8th and Eaton Avenues to come tumbling down, leaving behind a plume of dust in the air.

Crews used 485 pounds of explosives to demolish the vacant building.

It was a spectacle the community did not want to miss and some people dressed for the occasion.

The building’s reign came to an end after a nearly 50-year run. Martin Tower was the largest building in the Lehigh Valley since it opened in 1972 as Bethlehem Steel Corporations’ main headquarters.

“It represents manufacturing in the United States, which is now gone,” Doug Achui, of Bethlehem, said.

Edmund Martin, who the building was named after, joined Bethlehem Steel in 1922 and worked up the ranks, making Bethlehem a force in the industry.

“This is a company that built the Golden State Bridge and launched ships during World War II,” former Bethlehem Steel public affairs general manager Robert Bilheimer said.

Some residents were sad to see it go and wonder what will take its place.

“I spent time here when I was younger, lots of good memories,” Chelsea Kaufman said, “I hope they make something out of it.”

Duane Wagner, the project manager, and his team took ownership of the building in 2006 and planned to build retail, office and apartment space.

For now, the city begins the clean-up as it gets ready for a new chapter.

CBS3’s Crystal Cranmore contributed to this report.