�y��vlog

The gasholder worked this way: Coal gas was pumped into a wrought-iron, 120,000 cubic foot tank that floated atop water.

The world's oldest gasholder in London's Fulham Gasworks and a medieval timber-framed building in York have also made the annual list.

Gasholder number 2 at the Fulham gasworks is thought to be the oldest surviving gasholder in the world, having been built in 1830, but is now threatened by vegetation.

The 1888 Concord gasholder is believed to be the last of its kind in the country with its interior works intact.

The historical, architectural and technical background of the gasholder and its importance to the landscape led to it being granted protected status.