Where does this come from, and can I check it?

The 55 kilometre link includes a 6.7 kilometre tunnel under the seabed. The figure is taken from Guinness World Records, which is linked in full on this page. Every fact on Mondo Knows names its source rather than repeating an unsourced claim.

Is this really a records & extremes fact?

Yes. It sits on the Records & Extremes shelf, one of 2,600 sourced facts grouped into space, animals, the human body, history, science and more. Category pages collect every fact in the same field.

What else can I read about it?

The links under the fact point to a quiz, game, puzzle or calculator on the same subject, and the shelf below shows related facts. The wording here is original, and quoted phrases are marked as quotations.

Mondo Knows Facts

Hong Kong Zhuhai Macao is the longest sea crossing

The 55 kilometre link includes a 6.7 kilometre tunnel under the seabed The crossing opened in October 2018 and runs 55 kilometres across the Pearl River estuary, linking Hong Kong with Zhuhai and Macau. Vehicles disappear into an immersed tube tunnel for 6.7 kilometres between two artificial islands, allowing ships to pass above. The project took about nine years to build and includes three cable stayed bridges. It sits in Mondo's records & extremes collection, one of 200 facts that each trace back to the reference below.

Where this comes from

Guinness World Records

Facts that can change over time are reviewed and updated. If something here looks wrong, Mondo would rather know than be confidently incorrect.

Go further

Technology trivia World Geography trivia

More facts like this

Beipanjiang Bridge carries the highest bridge deckIts roadway sits 565 metres above the Beipan River in Guizhou The longest bridge in the world runs for 164.8 kilometresMost of the Danyang-Kunshan Grand Bridge crosses water on piers The Channel Tunnel is the longest undersea tunnelIts 50 kilometre bore links England and France beneath the seabed Norway's Laerdal Tunnel is the longest road tunnelIts 24.5 kilometre bore runs between the villages of Laerdal and Aurland The Gotthard Base Tunnel is the longest railway tunnelIts two bores run 57 kilometres beneath the Swiss Alps Norway's Ryfylke Tunnel dips 292 metres below the seaIt is the deepest subsea road tunnel in the world

Tags: bridges, china, tunnels

Hong Kong Zhuhai Macao is the longest sea crossing: the short answers

Where does this come from, and can I check it?: The 55 kilometre link includes a 6.7 kilometre tunnel under the seabed. The figure is taken from Guinness World Records, which is linked in full on this page. Every fact on Mondo Knows names its source rather than repeating an unsourced claim.
Is this really a records & extremes fact?: Yes. It sits on the Records & Extremes shelf, one of 2,600 sourced facts grouped into space, animals, the human body, history, science and more. Category pages collect every fact in the same field.
What else can I read about it?: The links under the fact point to a quiz, game, puzzle or calculator on the same subject, and the shelf below shows related facts. The wording here is original, and quoted phrases are marked as quotations.