If you mention Roman architecture and building construction what leaps immediately to mind are monumental buildings such as the Colosseum, the temples of the Forum(s), the Pantheon in Rome, the great aqueducts that stretch across the French countryside or through the city of Istanbul, or even buildings that no longer exist except in blockbuster HollyRome films, such as the Circus Maximus. The Romans, we learn at school, invented the arch; they put domes on top of buildings (even if they couldn’t quite place the last bit, leaving a hole through which rain has fallen on the Pantheon floor for centuries). They also invented cement and a quick-drying concrete that allowed them to erect quickly not only their temples, arches, and buildings on dry land, but also enabled the construction of underwater supports in harbours, such as the great one located at Ostia.

Roman buildings captured the imagination of contemporary locals as well as tourists as a mark of civic pride, peace and prosperity across the empire; they took their architectural show on the road to the farthest of the back and beyond, throwing up a wall that defined their northernmost boundary in Britain (begun in AD 122), and leaving behind edifices of slowly decaying grandeur attributed to, in Medieval legend, the creation of giants from an earlier, more prosperous age – the 8th-century Anglo-Saxon poem The Ruin, for example, laments romantically one such ruin, possibly the remains of the Roman bath in Bath, England, or the bath in the Roman town of Viroconium Cornoviorum, now sometimes referred to as the ‘Wroxeter Wreck,’ in Shropshire. Furthermore, many provincials across the empire built to type, emulating what they saw was the might of the city at the centre, hoping to impress, and leaving behind myriad theatres, temples, baths, and circuses of their own.

More interesting to me, however, are the mundane feats of architectural engineering: sewers, latrines, and hypocausts. One of the oldest constructions in the city of Rome is the Cloaca Maxima, ‘ the biggest sewer’ – it was probably built in the late-7th century BCE by the Etruscans who founded the city of Rome, and it is part of the sewer network that drained the marshes around the villages that became the city on the seven hills. Although the Romans didn’t realize it, these sewers helped to prevent malaria outbreaks in the City, as by draining the marshes, they cleared up the standing water that attracted mosquitoes. The aqueducts which fed into the city of Rome ultimately fed into the sewer system to carry away excess water from the baths and fountains. And finally, the sewers were also a good place to toss those public figures who had worn out their welcome; they would end up ultimately in the Tiber. The Cloaca Maxima is still in use today, but for drainage rather than body disposal, on hopes.

The Romans also made use of their sewer channels to create, more or less, continuously ‘flushing’ latrines; sometimes individual houses had a cramped toilet closet near the kitchen, which acted as a general waste-bin (there is an entire subfield of archaeology dedicated to toilet waste as all sorts of things would be thrown down the pipe), but as these cubicles rarely had a drainage run-off, they weren’t very pleasant. Instead, most people made use of public toilets with multiple seats, taking the opportunity to socialize while performing basic bodily functions. There is very little evidence of the infamous, shared sponge-on-a-stick that the Romans allegedly used to tidy up after a visit to the latrine, but most latrines did have a channel of running water circling the toilets for washing their hands and so forth. Emperor Vespasian, both a practical and frugal man, managed to put Rome’s finances into the black and pay for the construction of the Colosseum by instituting a toilet tax, specifically on urinating at the latrines at the Cloaca Maxima; when his son Titus complained in disgust about this practice, Vespasian waved a coin under his nose, asking if the smell offended him. When Titus answered no, Vespasian replied, ‘Yet it comes from piss [atque e lotio est]’ (Suetonius, Life of Vespasian 23.3.). ‘Le vespasien’ is modern French for urinal, another legacy of the Romans…

Finally, speaking of channelling water and directing it around the house, my favorite feature of Roman architecture are the hypocausts: the Romans developed a system of central heating that acted in a way similar to modern radiators that force hot water through a channel under one’s house. Because they were so expensive to maintain, hypocausts are mainly found in the villas of the wealthy or in public buildings such as the baths. They’re found in ruins on three continents across the Roman Empire. Hypocausts were not used by the Germanic tribes (not that they didn’t take advantage of natural hot springs when building their halls and palaces), and central heating disappeared in England, for example, between the 5th and the 19th centuries.

If you visit a Roman ruin, for example, the Palace at Fishbourne in Hampshire, England, or the Roman baths at Bath, you’ll see in some of the rooms a series of piles of flat stones or cement stabs. That is the hypocaust: these tiles held up the floor above and created a channel underneath the room. Fires were lit and the heat forced through channels under the house where water flowed. The water heated, and as it made its way through the house, the hot air and steam rose against the floor above, heating if not the floor, then the room or bath-pool immediately above. The warmest rooms were those closest to the fire. Lovely if you were a rich governor living your villa during a damp British winter or a patron of the city bath, not so much if you were the slave in charge of keeping alive and roaring the fire that provided the heat.

So the visible stuff is impressive – arches, columns, amphitheatres, temples, and the Romans were amazing engineers when it came to putting up a building quickly and efficiency – without neglecting its beauty – but the stuff underground is just as awesomely constructed if as important.

Carey Fleiner is a senior lecturer in classical and medieval history at the University of Winchester