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For those who are so inclined, there is a sporting pastime, which can be rated from "enjoyable physical exertion" to "suicidally extreme", called mountaineering. At the more accessible end of the spectrum, mountaineering overlaps rambling as a hobby and may well involve nothing more than a scramble up or down a steep incline connecting two footpaths - Eric Wheelbrace has probably done, approved of, sketched out, and written about, his share of this. Indeed, on Roundworld, the same mountain, such as Yr Wyddfa / Snowdon, might on one side present nothing more than an agreeable stroll to the summit, but on the other, a Category 3.5 climb on the universally accepted scale of difficulty.

This is all very well for those with access to the wilder hinterlands, but what of those who live in cities and whose busy lives cannot be interrupted for a six-month long expedition to the higher Ramtops? Ankh-Morpork has evolved its own urban version of mountaineering, which involves scaling the highest, steepest, trickiest and most difficult buildings in the city. This has its own version of the category scale denoting danger and difficulty - for instance, the ascent of the Tower of Art might rate a maximum 5.0 for the insanity/tired-with-life factor involved, whilst the dome of the temple of Small Gods is but a stroll for novices, rating a 2.8.

Indeed, once you have ascended to the weathercock atop the dome, take a moment to look around you as you bask in the stunning panorama of the Ankh-Morpork skyline. The bronze around you will have thousands of sets of initials, or full names and dates, scratched into it. Add yours, if you can find a space. For a close scrutiny will certainly find the names or at least initials of people who are now leading figures in the City. That single sans-serif "V" just by your left foot, with a date thirty years ago? The current Patrician. "D.Downey", also dated thirty years ago? The current Assassins' Guild president. And "Pteppicymon XXVIII, Viper House"? Realization sets in as to why edificeering is tolerated in the city and why there are so many signatures up here. It is an accepted means of training young Assassins - and allowing them to burn off surplus energies without actually inhuming anyone - and has been so for many years. Therefore it would be a brave or reckless building owner who objected to the exterior of his premises being so used. It would appear from events narrated in Making Money that edificeering is not just confined to assassins - Moist von Lipwig has taken up the sport to restore danger and thrill to his life. But Moist would not be covered by membership of the Assassins' Guild (ie, as one with a bona fide reason for scrambling about on my roof all night), and therefore runs the additional risk of being mistaken for an unlicenced thief. The possibility of being caught - or rescued - by vigilantes bent on delivering informal punishment, adds an extra frisson of danger that he relishes... It is possible the Thieves also require their school pupils to be competent in edificeering, for professional reasons of their own. (The thief Conina is said to have negotiated all the inherent hazards of the University roofscape, to make a clandestine entry and exit in order to steal the Archchancellor's Hat.

The Guild of Assassins has its unique "wallgame", which combines basic edificeering skills with football and which is played in one dedicated stretch of Guild wall.

There is also a negative version of edificeering that involves climbing in a downward direction, together with scrambling, crawling and contorting oneself in dark narrow places, which involves exploring all the layers of Ankh-Morpork that are below the current street level. On roundworld, this is called "pot-holing" if done outside the city. No name has yet been given to this mirror-inversion of edificeering, but "drainholing" has been suggested.

source:  https://wiki.lspace.org/mediawiki/Edificeering