Before you head to the impressive footbridge over the Lac du Der, you should first visit the Saint-Laurent church on the tip of the Giffaumont-Champaubert peninsula. The Lac du Der-Chantecoq is the largest artificial lake in France. It was created in 1974 to regulate the flow of the Marne and thus prevent flooding in Paris. To do this, three villages – Chantecoq, Nuisement-aux-Bois and Champaubert-aux-Bois – had to be demolished. Of these villages, only the church of Champaubert-aux-Bois was preserved, which now stands on a peninsula in the lake. The Saint-Laurent church, built in the 12th century, is one of the few buildings to have survived the construction of the lake. Today, the church offers a beautiful view over the Lac du Der. The route takes you over the beautiful footbridge to the Base Nautic, from here you follow the edge of the water to end up in a forest. Once you come out of the forest, you continue walking towards a water tower. At the water tower, a large old chimney is somewhat hidden. This chimney was used in the past as a geodetic chimney; the smoke from the chimney allowed geodetic measurements to be taken for making maps. On a wide unpaved road, you continue walking towards the village of Giffaumont. At the church, there are beautiful picnic benches in a botanical garden. Further into the village, you will pass some charming half-timbered houses. This building style originated between the 15th and 19th centuries, partly due to the lack of quarries in this wet region. Instead, people used the abundant wood from the surrounding forests, filling the wooden structures with a mixture of straw and loam. From the village, you walk along the shore of the Lac du Der to the marina at the Base Nautic to return to the starting point.