In a catalog assembled for the 2014 Venice Biennale to accompany an exhibition on architectural elements, the bathroom is referred to as “the architectural space in which bodies are replenished, inspected, and cultivated, and where one is left alone for private reflection - to develop and affirm identity.” I think that means it’s where you watch yourself crying in the mirror. As for the toilet specifically, Biennale curator Rem Koolhaas and his researchers, consider it to be the “ultimate” architectural element, “the fundamental zone of interaction--on the most intimate level--between humans and architecture.” So the next time that burrito doesn’t sit right or you had one too many gin and tonics, remember that you’re experiencing a corporeal union with the mother of all arts. Potty humor aside, the privatization and proliferation of the bathroom has really driven new developments in cleanliness and safety and has shaped our buildings.

The flush toilet was invented in 1596 but didn’t become widespread until 1851. Before that, the “toilet” was a motley collection of communal outhouses, chamber pots and holes in the ground. During the 11th-century castle-building boom, chamber pots were supplemented with toilets that were, for the first time, actually integrated into the architecture. These early bathrooms, known as “garderobes” were little more than continuous niches that ran vertically down to the ground, but they soon evolved into small rooms that protruded from castle walls as distinct bottomless bays (such a toilet was the setting for a pivotal scene in the season finale of "Game of Thrones"). “Garderrobe” is both a euphemism for a closet as well as a quite literal appellation, as historian Dan Snow notes: "The name garderobe - which translates as guarding one's robes - is thought to come from hanging your clothes in the toilet shaft, as the ammonia from the urine would kill the fleas."

Though it might be named for a closet, the garderrobe actually had a strong resemblance to an aspect of a castle’s defenses. And it works in the same basic way: gravity. And while the garderobe was actually a weak spot in a castle’s defenses, woe be the unassuming invader scaling a castle wall beneath one. Several designs emerged to solve the problem of vertical waste disposal - some spiral up towers, for example, while some were entire towers; some dropped waste into cesspools, moats, and some just dropped it onto the ground below. Not all medieval compounds were okay with merely dumping excrement onto the ground like so much hot oil. Christchurch monastery (1167) has an elaborate sewage system that separates running water, rain drainage, and waste, which can be seen marked in red seen in the below drawing, which has to be the most beautiful plumbing diagram I have ever seen:

Today, the toilet has been upgraded from architectural polyp to a central design element. A long time ago, when I had dreams of becoming an architect, I was designing a house for a client who wanted to see the television from the toilet and tub but did not want a television in the bathroom. The entire master suite, and thus a large percentage of the building’s second floor, was designed around seeing the views from the bathroom. And that was the second residence in my short career that began with the bathroom. More commonly though, toilets shape the spaces of our skyscrapers.

Because we can’t simply drop our waste 800 feet off the side of a skyscraper onto a busy metropolitan sidewalk, and because efficient plumbing depends on stacking fixtures that share a common “wet wall,” toilets (and elevators, of course) are the only elements drawn in the plans for high-rise buildings, whose repeating floor slabs are built out later according to a tenant’s needs. Once relegated to the periphery, the toilet is a now an oasis at the center of our busylives, a place where, as Koolhaas wrote, “one is left alone for private reflection - to develop and affirm identity.” To paraphrase Winston Churchill, we shaped our toilets, then our toilet shapes us