Wilting in the summer sun, a line of tourists waits to climb Notre Dame cathedral and meet its gargoyles.

Four meters (13 feet) beneath them, a team of archaeologists is digging the other way – straight down and back in time, to Roman Paris 2,000 years ago.

In 2019, fire brought Notre Dame’s spire crashing down as the world watched. The cathedral was rebuilt and reopened in late 2024 and now Paris wants to soften the hot, bare square in front of it with trees and shade.

But in a city this old, the soil cannot be turned until what lies beneath it is excavated, in case it is damaged during works.

So a slice of Notre Dame’s forecourt has become an excavation site – an open pit ringed by barriers and crossed by a wooden walkway, a few steps from the line-up.