Smells are brilliant and infuriating for writers because they are just so hard to express. Here’s an Atlas Obscura piece, an excerpt from Jessica Leigh Hester’s Sewer, describing the waft of fatbergs that clog the pipes beneath London.

You can live with the smell of poop, Howard said. Over time, it even starts to smell sweet, he claimed. You get used to it.

No one gets used to the stench of a fatberg.

It’s a foul buffet. There’s the stink of rotting eggs, courtesy of hydrogen sulfide. Then, something cooked in old, rancid oil. “It’s the smell of fries, constantly bombarding you,” Howard said. (Maybe—but cold, greasy, and laced with poop.) Gases get trapped beneath a crust on top of the fatberg, Stuart explained. Step too hard and the crust can break, inviting eruptions. Some gases, like methane, are odorless at room temperature. And when other smells are so spectacularly and constantly bad, the nose is no longer a good barometer of danger.

These moments that overwhelm the senses are fascinating.