Another characteristic is the atmosphere. It's often dark, damp, and a bit spooky. The subterranean environment can be claustrophobic, which adds to the tension. Characters may face unknown threats, such as strange creatures that have evolved in the underground. And the archaeology part means there's a race against time to preserve or study the findings before something bad happens, like the site collapsing or thieves stealing the artifacts.
Archaeology brings in the aspect of history. These novels often involve the discovery of ancient artifacts or civilizations. In a subterranean setting, these artifacts might be related to long - lost underground cultures. They also have adventure elements like characters facing physical challenges, like climbing through narrow passages or dealing with underground waterways. The combination of these elements makes for exciting reading.