A trans-Atlantic tunnel, connecting cities like New York and London, is currently deemed impossible with existing technology. The required speeds for a feasible travel time necessitate advancements in train technology. Current tunnel-boring machines are too slow, and the immense water pressure at the Atlantic's depths poses significant, potentially catastrophic risks. The Channel Tunnel, currently the longest undersea tunnel, provides a stark comparison, highlighting the immense scale and cost of even shorter projects. The sheer logistical challenges, including power supply, ventilation, and worker transport, coupled with the astronomical costs, render the trans-Atlantic tunnel a distant prospect.

Prepared by Jonathan Pierce and reviewed by editorial team.