Trains might be a reasonably cheap transport option - but rail infrastructure is very costly to build. Monorail, maglev systems and high speed rail are more expensive again - and prices really skyrocket when you have to build bridges, tunnels and winding mountain routes, or cover difficult terrain. Which is why Anatoly Unitsky's String Transport Systems look like they've got so much potential. The system uses solid steel/concrete rails, reinforced with extremely high tension steel wires, to provide an efficient and smooth rail system anywhere between 3 to 30 meters above the ground. It's earthquake, hurricane and terrorist-proof, and capable of supporting vehicle speeds over 500 kmh, too, making it a genuine high-speed rail alternative, for a fraction of the price of road or ground rail alternatives. Fascinating stuff!