Sailing from the port city of Le Havre to Rouen, you can experience the deep history of France’s second-longest river, the Seine, which stretches nearly 780 kilometers (485 miles) from Normandy to Burgundy. Le Havre, heavily bombed in World War II, was entirely rebuilt in the modernist style by architect Auguste Perret, and was named a UNESCO World Heritage Site in 2005. At the waterway known as the Crique de Rouen, where the Seine flows into the English Channel, is Honfleur, a charming harbor town brimming with narrow timber-frame town houses dating from the 16th to the 18th centuries. The river then meanders through the Parc Naturel Régional des Boucles de la Seine Normande, an 80,000-hectare (198,000-acre) expanse with richly diverse landscapes, from deep valleys to tree-lined hills to sweeping meadows.Punctuating this picturesque scenery are the thatched-roof cottages and old churches of historic villages, as well as ancient stone abbeys and stately châteaus. Rouen, the capital of Normandy, rises up from the banks of the Seine like a painting—in fact, it was a favorite subject of French Impressionist Claude Monet. First among the city’s many important Gothic churches is the Rouen Cathedral, whose distinctive cast-iron spire and two towers pierce the sky.