The only bridge on that list even remotely comparable is the Hong Kong-Zhuhai-Macau Bridge. The rest are essentially elevated highways which are almost entirely

The only bridge on that list even remotely comparable is the Hong Kong-Zhuhai-Macau Bridge. The rest are essentially elevated highways which are almost entirely over land. I am not a civil engineer so this is just some uninformed speculation: - The channel goes to about 45m deep between Dover and Calais, while the path of the HK bridge only goes to about 20m depth. - The bay formed by the Pearl River is more enclosed and protected from weather than any part of the channel. - The bridge would need sections elevated high enough for future mega container ships. - The HK bridge cost $15.9b. I'd expect the channel bridge to cost much more. It might be cheaper to just build another tunnel. Edit: and, of course, by the time I finish this comment there are 10 more saying basically the same thing.