bridges

The longest bridge on Earth runs for 164 kilometres — roughly the distance from London to Birmingham — carrying high-speed trains across the rice paddies and rivers of eastern China. The Danyang–Kunshan Grand Bridge is so long that calling it a 'bridge' almost understates it; it is an elevated railway the length of a small country. But the real engineering drama lies elsewhere: in the bridges that span the widest single gaps without touching the ground.

The Burj Khalifa in Dubai stands 828 meters tall — for context, you could stack almost two Empire State Buildings on top of each other and still not reach its antenna. But height is only one dimension of 'largest.' The world's longest bridge stretches 164.8 km across China. The Great Wall of China, including all branches, runs over 21,000 km. The largest building by floor area is a Boeing factory in Washington State that covers 398,000 square meters under a single roof. What engineering limits the next record depends on which dimension you're measuring and why physics makes every additional meter harder than the last.

Bridges carry millions of people safely every day. Here's the remarkable engineering behind why they hold.