There are thousands of industrial chimneys in the Czech Republic, with many dating back to the late 19th Century - most are no longer used and a group of enthusiasts spend their weekends climbing the structures. Alastair Lawson joined them in Zelezny Brod, but soon regretted it.
I am 40m (130ft) up a 120-year-old chimney in the north-east of the Czech Republic and I am having a minor panic attack. My legs feel like lead weights as I look down on the tiny figures on the ground below me.
"Are you coming up or going down?" asks my guide, Martin Vystejn, as I cling for dear life on to the ladder.
The fear gripping me is so overpowering that my inclination is to do neither and remain suspended in mid-air about two-thirds of the way up the 52m (170ft) disused industrial chimney.
The other climbers seem unruffled by my agony and continue nonchalantly to make their ascent, neatly bypassing me on the ladder as I scuttle downwards.
So how did I end up in this predicament?
few weeks ago, I read a Czech media report about the activities of the Union of Czech Chimney Climbers, a club set up mostly to climb, but also to survey and lobby for the preservation of the country's 5,000 to 6,000 industrial chimneys.
They invited me to join them as they scaled two disused textile factory chimneys located alongside each other in Zelezny Brod, north-east of Prague.
Every weekend and bank holiday the climbers meet at the base of a different chimney. They are men and women from all walks of life, including graphic designers, shopkeepers, accountants and students. The one thing they have in common is a passion - verging on an obsession - for being high up above the ground.
The age range is equally diverse - from teenagers to a 76-year-old former track-and-field athlete who whizzed up the ladder at high speed, making me feel even more inadequate.