Nine crossings with no easy way to build them: over sea ice, across an active fault, over gorges half a kilometre deep. The last one was started with a rocket.
The Atlantic Road hops island to island on eight bridges. Twelve hurricanes hit the site during the six-year build, and the 260 m Storseisundet span was the worst of it.
Northumberland Strait freezes over every winter. Canada's 12.9 km Confederation Bridge rests on cone-shaped piers that split drifting floes before the ice can shove it.
Halfway to Denmark the motorway simply dives. Oresund runs on piers, then disappears into a tunnel under a man-made island, leaving shipping and flight paths clear.
The Hong Kong-Zhuhai-Macau link is the longest sea crossing ever built. Mid-route it drops into a 6.7 km undersea tunnel so container ships keep their channel.
The 1995 Kobe quake pulled Akashi Kaikyo's towers further apart while the deck was still unfinished. Engineers redrew it, and the span opened a metre longer at 1,991 m.
Turkey's 1915 Canakkale Bridge hangs 2,023 m between towers over the Dardanelles. That figure is deliberate: it marks the republic's centenary in 2023.
Rather than drop into the Tarn valley, France flew over it. Millau's deck sits 270 m up and its masts reach 343 m, taller than the Eiffel Tower. Mist often sits below.
India's Chenab arch carries trains 359 m over the river, 35 m higher than the Eiffel Tower's tip. It is built for 266 km/h winds and to stay up if a pier is destroyed.
The Sidu gorge was too wide to string a line across by hand or helicopter. In 2006 crews launched rockets trailing 1,300 m ropes. The deck now sits 496 m above the water.
Each of these was a hole in the map that nothing could cross, like the Duge bridge here mid-build, 565 m over the Beipan River.