Drawings in red chalk in the underground quarry Herblay.
- Junction of the south passage.
- Martha Street.

The construction of the castle Regnéville-sur-Mer dates from the ninth century. The castle was the witness of many battles between French and English during the Hundred Years War. In the 17th century, the fortress was destroyed by order of Cardinal Richelieu. One wall of the castle flew to the bottom of the church. Today, there are only very little of the original castle (there is a tower collapsed at half) but this crypt is still beautifully preserved.

The origin of the silver-lead mines Trémusson is Roman. It was already long pieces of Roman origin in the galleries. An excavation site has confirmed the original site, by the discovery of tiles to hook on both sides of the creek.

In the late 17th century, the English are precursors in the mining of nonferrous metals. They buy logging concessions in Britain. However, the site is still not exploited Trémuson. The concession is then awarded on 1 April 1732 to a Breton of Morlaix Guillotou of Kerver. Speculation around the precious metal is growing, which does not prevent the owner from going bankrupt due to a bad investment.

In 1740 the Mining Company of Lower Britain bought the concession. It will take 40 years to industrialize the mines. In 1782, more than 500 people work at the mine site. The size of the concession is over 90,000 hectares. It will never be fully exploited. At the end of the 19th century, the exploitation fall. The owners regularly change without success.

It was not until 1922 that the operation resumes. A laundry room is built on a hillside in 1924. She can wash the ore and the sort because the deposit is less rich than in ancient times. A year later, a foundry was built. The operation is successful for ten years, then the company suffers Dufourg the general crisis. In 1931, the mine was permanently closed. It will never be exploited.

Today, the mines are protected refuges for bats but the many miles of tunnels continue to drain the lead in the village by water infiltration. The villagers can not eat vegetables from their gardens or drink water polluted groundwater. There are remains of the laundry and the foundry behind the village.

source: patrimoine.region-bretagne.fr(FR)

Quarries of Herblay are over 14km wide and some hundreds of meters deep, on hillsides along the Seine.

In 1776, the exploitation of new underground quarries in Paris was forbidden. People had to take the stone elsewhere. It is for this reason that the quarry was known as "Imperial quarry" or "Quarry of the city of Paris". They built many monuments in Paris with this stone because it was high quality (the famous Royal stone).

Among the monuments built, there was The Pantheon of Paris, Department of Marine Place de la Concorde, the Gare de l'Est, the mint as well as many statues at Versailles.

The network's quarries has been excessively exploited in Herblay. The ceiling is fragile and the walls separating the tunnels are very thin. To reinforce the quarry, they have added many pillars and reinforcement structures.

Later, like many underground quarries, they served to mushroom plantation in the 1980s. The workers have dug additional corridors between small quarries networks.

A few years later and they were gradually abandoned. The latest mushroom plantation closed in 1995.

Since 2003, the association "Herblay heritage" has undertaken to make public visits to the part of the "English entry" with the famous double-arched vault and pretty ponds.