This looks a bit like a giant ear canal, but in a way, it's the opposite. It's the largest horn in the most powerful sound system in Europe. The system's maximum output, according to the European Space Agency, would kill any human exposed to it.
The horn is part of the European Space Agency's Large European Acoustic Facility in Noordwijk, the Netherlands. The facility blasts sound at spacecraft components to test whether they're able to withstand the intense noise of launch. There are four horns, to create sounds in a range of frequencies. ESA engineers send nitrogen gas through the horns to create noise of more than 154 decibels.
Whether that's enough to literally kill is unclear. (There are so many variables. Did the agency mean "kill you on contact" or "kill you if you're sealed inside the facility for a while"?) At the very least, it would cause some serious damage. The eardrums rupture at around 150 decibels. The lungs rupture at around 200 decibels.
For safety, the facility has half-meter-thick walls made of steel-reinforced concrete coated inside with epoxy resin, which reflects noise into the chamber. It also won't operate unless all of its doors are closed.