"You do realise we have a retractable roof, don't you?"
It's an outrageous claim. We've just scaled the great arcing canopy of Olympia and stand a few inches beneath its apex. The west London exhibition hall is a Grade II listed masterpiece of Victorian engineering. Its vast curving roof contains 85 tons of glass, delicately interposed on a 130-year old iron frame. No way is this crystalline leviathan retractable.
"It really is. Watch."
Our guide, Steve Ward, pushes a button. A hiss of air from some hidden hydraulic system briefly makes us jump. And then a large section of Olympia's roof begins to move. Even the centre's marketing manager is taken by surprise.
It's a final highlight of a vertiginous tour of the complex. Wearing safety harnesses and cable climbing kit, we dodged girthsome air vents and negotiated ladders of alarming wobble, all to reach the roof gantries on top of Olympia Grand, the main exhibition space at Olympia. Most of London is visible from up here.
The internal view is also quite magnificent: 1,200 tons of white-painted iron arch around us, all resting on giant ball-and-socket joints beneath the floor. Steve relates how he would clamber around on the internal beams without any rope or helmet, in the years before health and safety rules were tightened, a thought that makes the stomach churn.
This great venue in Kensington opened in 1886 as the National Agricultural Hall. It has since hosted countless shows, rallies and exhibitions. The space has variously been occupied by lions, fascists, pigeons, boxers, a Bedouin encampment, aircraft, and Mr Charles Crufts' sporting dogs. Many remarkable diversions have passed through this venue over the past 125 years, but the structure itself is perhaps the greatest wonder.
Olympia is set to play an even more prominent role in the years to come. Nearby Earl's Court exhibition centre has now been demolished, and exhibitions such as the Ideal Home Show have moved to Olympia. We're not sure how many of them will make use of the retractable roof, however.
Other Londonist rooftop adventures
- Up on the roof of Victoria station.
- Up on the roof of King's Cross station (2013).
- On top of the Truman Brewery.
- Up on top of the Walkie Talkie (2012)
Got an interesting roof? Why not show us around?