Just about a mile down the river, construction is moving forward on Blackfriars Station, the world's largest solar bridge.

ENGADGET: Inhabitat's Week in Green: rise of solar power, cardboard forts and a Death Star ping pong ball

We also showcased several feats of futuristic architecture -- a skyscraper zoo with a built-in ferris wheel and a shape-shifting solar bridge that purifies the air.

ENGADGET: Inhabitat's Week In Green: solar-powered stadium, bipod flying cars and biofueled flights

The historic bridge is being fitted with a solar array that will produce 900, 000 kWh of clean electricity per year.

ENGADGET: Inhabitat's Week in Green: rise of solar power, cardboard forts and a Death Star ping pong ball

Boone Pickens has argued for years that natural gas is the best immediately available economic and environmental solution for U.S. energy needs, a bridge over oil and coal to the future when alternative solar, wind, and nuclear power will be ready to take over more of the load.

FORBES: Technical Picture Looks Pretty For Natural Gas

Energy Secretary Steven Chu, speaking here this morning, touted gas as a bridge fuel to get us between coal and a wonderland of solar panels on every roof and windmills in your backyard.

FORBES: ConocoPhillips' Mulva Talks Up Gas

To hear the environmental stalwarts tell the story of the future, natural gas is supposed to be our bridge fuel to a bright new world of renewable energy, with solar panels on every roof and windmills in every town.

FORBES: Coal Is History. Or Is It?

Clean-burning natural gas, he said, will serve as the bridge fuel to take us from reliance on oil and coal to alternatives like solar and wind.

FORBES: Energy Sec Chu Says Global Warming Is Real; Nat Gas Will Be Bridge Fuel