Decades ago, a wrecking ball was the only way to bring down a building. It was a slow process that was guaranteed to provide plenty of dust and debris to the local neighbourhood, and it was also a costly way to clear out old structures. Many older buildings were made of concrete blocks and steel, so the wrecking ball had to swing many times before an old wall would come down. Modern developers have found that some smaller projects can still be demolished this way, but many of them come down faster, easier and with less dirt and debris when implosion is used.
Imploding a building is a serious undertaking, and experts in demolition are used to do the work correctly. After a building has been gutted of anything that can be reused or recycled, they study the structure to determine how best to bring it down. Their task is to ensure the inside structure completely collapses, and their plan is that the outside of the structure will collapse inward. Experts remove enough internal support before they set off their charges to ensure everything falls in accordance with their plan.