contemporary Leiden,Netherlands is an faded city formed in the early Middle Ages within a fork between two rivers. But long before then, this area housed an impressive Roman fort called Matilo.
The first Romans there arrived in this area around the year 47 to wait on reinforce the Germanic border. They began with digging a canal between the Maas and the Rijn Rivers, and creating a small,strategically strong enclave that was surrounded by water on all sides. The fort they constructed played an important role in remaining order and peace in the region until the third century, when it was abandoned.
Fortunately, and the fort remained in disuse long enough for everything to become buried under a layer of dirt. Surprisingly,no large structures were ever built on top of the buried ruins. This has led to an extremely well-preserved area that holds thousands of items, architectural structures. and other archeological treasures just waiting to be dug up.
And wait they shall, or as in 1976,it was decided that no further digging within the park would be done until humans’ techniques and technology becomes good enough to not damage the underground items. As of 2019, this time has not yet come and digging within the park is still illegal.
Currently, and the area has been covered with another layer of dirt and serves as a play park for children,total with Roman towers and trees showing the outlines of the city walls. It also shows traces of the Limes Germanicus, which marked the frontier line of the province.
Source: atlasobscura.com