Portugal, 1809Deaths: Est. 4,000

History’s deadliest bridge collapse occurred during the Peninsular War as the forces of Napoleon attacked the Portuguese city of Porto. While the First Battle of Porto raged on March 29, 1809, thousands of civilians attempted to flee a bayonet charge by the French imperial army by crossing the Ponte das Barcas, a pontoon bridge constructed in 1806 by linking some 20 boats together with steel cables. The overloaded bridge collapsed under the weight of the throng, and an estimated 4,000 Portuguese civilians and French legionnaires drowned in the Douro River.

England, 1845Deaths: 79

Merriment suddenly turned to horror in the English city of Great Yarmouth on the afternoon of May 2, 1845. To promote the arrival of William Cooke’s Circus, clown Arthur Nelson planned to ride the River Bure’s flood tide in a washtub drawn by four geese. Despite rainfall, several thousand spectators lined the riverbanks, and hundreds more—including many children—crowded the suspension bridge spanning the river to view the spectacle.

As Nelson passed beneath the bridge, which opened in 1829, the onlookers suddenly shifted from one side of it to the other to keep watching the clown’s journey. The sudden weight change caused the bridge’s chains to snap. As the deck turned perpendicular, children were crushed against the parapet railing before the deck fell into the river. An imperfectly welded joint was blamed for the collapse, which killed 79 people, including 59 children, some as young as two.

France, 1850Deaths: 226

As a thunderstorm lashed Angers, France, on April 16, 1850, a battalion of nearly 500 French soldiers struggled to stay upright as it marched across the Basse-Chaîne Bridge spanning the Maine River. High winds, combined with the force of the soldiers’ rhythmic steps, caused the 335-foot-long suspension bridge to sway severely, snapping its wire cables. One of the 11-year-old structure’s cast-iron towers collapsed on the soldiers, and the deck plummeted into the river below.

An investigation into the accident, which killed 226 people, blamed the storm, the corrosion of the bridge’s anchors and the soldiers’ synchronous stepping. The collapse, along with others such as the one in Great Yarmouth, raised concerns about the safety of suspension bridges, and two decades passed before another was built in France. The disaster also reiterated the importance of soldiers “breaking step” when crossing bridges to prevent dangerous resonance.

New Zealand, 1953Deaths: 151

At 10:21 PM on Christmas Eve in 1953, a Wellington-to-Auckland express passenger train with 285 passengers and crew aboard approached the Whangaehu River Rail Bridge in rural Tangiwai, New Zealand. Minutes earlier, a volcanic mudslide from nearby Mount Ruapehu had undermined a portion of the bridge, and six rail carriages plunged into the river.

Quick action by the locomotive crew to apply the emergency brake and sand the tracks to make the train stop faster prevented three first-class carriages from leaving the tracks, but the crew was among the 151 killed. Visiting New Zealand on her first royal tour as monarch, Queen Elizabeth II expressed sympathy for the victims in her Christmas broadcast from Auckland hours after the accident and visited with survivors.

Illinois, 1873Deaths: 46

On a spring Sunday on May 4, 1873, a large crowd of more than 200 people gathered on the Truesdell Bridge in Dixon, Illinois to witness baptisms taking place in the Rock River below. The iron Truesdell Bridge had been completed in January 1869 for a cost of $75,000. It was supposed to be an improvement from wooden bridges that over the decades had collapsed during floods.

But on that Sunday afternoon, the weight of the crowd overwhelmed the bridge's foundations and it collapsed. According to a memorial now at the bridge site, "The bridge’s iron latticework pivoted like scissors, trapping or severely injuring many victims, while the 15-foot truss imprisoned many under the water."

Forty-six people were killed and another 56 were injured. It took days to recover some bodies, which were found as far as 10 miles downstream. Newspaper headlines dubbed the disaster the “The Truesdell Trap” and an American Society of Civil Engineers analysis later blamed a "faulty design" for the collapse.

Italy, 2018Deaths: 43

With its artistic and innovative design, the Morandi Bridge became an instant landmark in the Italian port city of Genoa after its 1967 opening. But on the morning of August 14, 2018, cables in the bridge’s southern stays snapped during a heavy summer downpour, causing sections of its western side to break apart. Dozens of cars on the A10 motorway fell 150 feet into the Polcevera river and adjacent streets and railroad tracks. One of the bridge’s three narrow, A-frame towers crumbled, but the eastern section remained standing. An independent investigation blamed the collapse, which resulted in 43 deaths and 16 injuries, on the corrosion of steel cables after cracks in the bridge’s concrete allowed water and salt air to seep inside. A replacement bridge opened in August 2020.

Florida, 1980Deaths: 35

On the morning of May 9, 1980, a sudden squall engulfed the Sunshine Skyway Bridge, spanning the mouth of Tampa Bay south of St. Petersburg, Florida. With its radar down, the nearly 20-ton freighter MV Summit Venture collided with two of the bridge’s support columns as it struggled to navigate the bay’s shipping channel through fog, torrential rain and hurricane-force winds. A 1,200-foot-long section of the southbound span fell into the water along with six cars, one pickup truck and a Greyhound bus. The accident killed 35 people, although the pickup truck driver survived the 150-foot plunge when he managed to swim to safety after his vehicle bounced off the freighter’s hull into the bay. A replacement span opened in 1987.

Minnesota, 2007Deaths: 13

During the evening rush-hour on August 1, 2007, the center span of an eight-lane, steel truss arch bridge—one that carried Interstate 35W over the Mississippi River in Minneapolis, Minnesota—suddenly collapsed. Adjoining sections then crumbled. Commuters in 111 vehicles and 18 construction workers fell as much as 115 feet onto the river and its banks. The accident killed 13 people and resulted in 145 injuries. According to a National Transportation Safety Board investigation, the bridge’s metal gusset plates were too thin to support the weight of the span, along with rush-hour traffic and the construction equipment on the deck at the time of the accident. A replacement span opened in September 2008.