This 1934 British newsreel showcases the "canal brigade" of Vienna, Austria, braving the bowels of the city, a common hiding place for criminals at the time.
Most interesting to us was the squad's frequency of finding "tramps," men who would walk the murky tunnels in search of coins and trinkets citizens would lose down the drain. But rather than arresting them or escorting them out, they were merely searched and regularly permitted to carry on.
...All being well, they are allowed to proceed with their very exclusive occupation.
While our current sewer crews are not in search of criminals, dangers persist. Next time you walk over a manhole, think about the unseen underworld and the sewer maintenance "canal brigade" still at work today.