Scientists worry a volcano may erupt on the Spanish Island of La Palma.
In recent days, nearly 400 million cubic feet of magma have seeped into the Cumbre Vieja national park, south of the island.
And in the past weeks, more than 4,000 tremors have been detected near the Teneguia volcano - one of the most active volcanoes in Spain that last erupted in 1971.
The "swarm" of earthquakes, and the shallowness of the seismic activity, has authorities on edge.
They declared a yellow alert for volcanic eruption, the second of a four-level alert system.
And they have told residents, like this shopkeeper, to be prepared for an evacuation.
"I've been told to have some clothes packed, to have my insurance card, medication, ID, and the title deeds ready to take with us, because nobody knows what can happen. The moment they tell us to get out, we'll leave."
Any evacuation plan if activated would involve moving 40,000 people.
In the meantime, scientists are doing everything they can to understand the activity beneath the ground.
This scientist is injecting a syringe into the earth, extracting gas in order to analyze it in the lab.
She says she hopes to find out what type of gas there is, especially those of volcanic origin, and its concentration to understand anomalies causing the recent activity.