On the shores of the Baltic Sea, in the south of Denmark, a vast engineering marvel is taking shape — piece by giant concrete piece — that, when finished, will drastically redraw the road and rail ...

(CNN) — Descending up to 40 meters beneath the Baltic Sea, the world’s longest immersed tunnel will link Denmark and Germany, slashing journey times between the two countries when it opens in 2029.

China is building the world’s longest undersea tunnel to link Dalian and Yantai, reducing a six-hour journey to just 40 ...

Editor’s note: Sign up for Unlocking the World, CNN Travel’s weekly newsletter. Get news about destinations, plus the latest in aviation, food and drink, and where to stay. On the shores of the Baltic ...

At 18 kilometers (11.2 miles), it’s nowhere near as long as the 50-kilometer (31-mile) Channel Tunnel, but in many other ways it’s bigger. The project will, in fact, be the world’s longest road and ...