When wealthy travelers embarked on the Grand Tour of Europe in the 17th and 18th centuries, one popular stop near Naples was the Cave of Dogs. Here, local guides would happily demonstrate the cave’s accumulation of carbon dioxide by suffocating dogs in the fumes, before hopefully reviving them in the waters of the nearby lake.
The Cave of Dogs (Grotta del Cane) is a small cave near Pozzuoli, Naples. Inside is a fumarole that spews out carbon dioxide, which, being heavier than air, accumulates in the lower, deeper parts of the cave. Back in its heyday, visitors would typically visit this strange cave as part of a tour of the volcanic Phlegraean Fields.
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