While the construction and design fails on this list might seem funny, in real life, poor design, construction, and cheap materials can be very unsafe, costing thousands of lives. Throughout history, buildings have collapsed due to ignored warnings, construction, and design flaws that could’ve been avoided. These structures collapse because someone responsible overlooked something important—they’re almost never at random.
For example, the deadliest structure collapse in human history, which cost about 20,000 lives, occurred because of a cheap wooden construction that wasn’t able to withstand the number of people that crowded it. It was the Fidenae amphitheater in Italy, and it remains a historic example of why crowd loads and construction oversight matter.
The second, a more recent instance, is the Ponte das Barcas, a bridge that was located in Porto, Portugal. It collapsed in 1809 when thousands of civilians tried to escape from French troops through it.
Its design might be the reason why it collapsed, as it was made out of wooden boats connected together, so it could be easily disassembled and reassembled. It collapsed due to the weight of too many people, costing around 4,000 lives.
The third deadliest construction collapse, which took around 2,000 lives, was when the South Fork Dam gave way after days of relentless rain. Its owners have previously lowered the weight, used poor materials, and neglected to maintain it, which caused the dam to collapse and release about 20 million tons of water in minutes, flooding the valley where people lived.
It’s known as the Johnstown Flood—one of the deadliest civil engineering failures in U.S. history.
Similarly, around 2,000 people died in Italy when a huge wave over 250 meters high surged over the Vajont dam and crashed into the villages below due to a landslide in the water reservoir. It happened because the people responsible for it ignored the warnings of the unstable mountain and kept filling the reservoir. While the dam remained intact, it became a turning point in how engineers assess slope risk around reservoirs.
The following deadly structure collapse happened in 1807 in Tokyo, Japan, when a festival crowd gathered on Eitai Bridge to watch fireworks. Since the bridge was made out of wood without crowd control in mind, it collapsed under the weight of festivalgoers. The incident caused nearly 1,500 people to drown. After that, the country introduced stronger bridge designs and began recognizing crowd control as part of safe urban planning.
Just a bit more than 10 years ago, in 2013, in Bangladesh, a commercial building, Rana Plaza, collapsed and took 1,134 lives with it. The night before, engineers recommended evacuation as cracks were noticed in its walls. Despite this, over 3,000 workers were told to return to work the next morning. Within hours, the building gave way due to overloaded floors, illegal expansion, and substandard construction.
