Meaning of sub-aqueous | Babel Free

Examples

“The tunnel is 4 miles 628 yd. long, and is the longest tunnel on a British main-line railway, and the longest sub-aqueous tunnel in the world.”

“[...] he'd been hoping to build a bridge over the River Nova in St Petersburg. The Russians would eventually decide to go under the river, but not before Brunel had shown the way, by building the first sub-aqueous tunnel in the world.”

CEFR level