In 2009, while installing elevators in Madrid’s Opera metro station, construction workers came across a slice of the city’s past buried over 26 feet below Plaza de Isabel II. Excavations revealed the Fountain of Caños del Peral, a fragment of the Amaniel Aqueduct, and bits of the old Arenal Sewer.

The fountain of Caños del Peral is perhaps the jewel of the collection. It was built in the second half of the 16th century and has an uncut stone façade in the typical Renaissance style. The fountain was located in a little square where the city’s water carriers gathered to collect water, which they then delivered around Madrid.

The other two archaeological treasures are also linked to the city’s relationship with water, particularly with the Arenal Stream. The stream, which came from what’s now Puerta del Sol (the very heart of the city) crossed the square of Caños del Peral via a deep ravine.

Waste was thrown into the stream, causing pollution and blockages that led to flooding. To help remedy the issue, in the 16th century, a sewer system was created. The Amaniel Aqueduct was built in the beginning of the 17th century to cross the ravine. Its construction was essential, as it supplied additional much-needed drinking water to the city.

Today, these three archaeological relics are displayed within the Opera metro station behind glass panels. Locals and tourists alike can take a few moments to look at them and their accompanying informational signs to add a bit of history to their commutes.