This document discusses submerged floating tunnels, which are tube-like structures that float underwater and are fixed in place. They are designed using Archimedes' principle of buoyancy to float at a certain depth and accommodate road or rail traffic. The tunnels are constructed in sections that are joined together and anchored to the seafloor with cable systems. Submerged floating tunnels allow for transportation connections in very deep waters where conventional bridges or tunnels are not feasible. They have advantages like avoiding disruptions to ship traffic and reducing environmental impacts compared to surface structures.