The Steinhuder Meer is the biggest lake in Lower Saxony, and it is shockingly shallow: for most of its area it is no more than a couple of metres deep, so that on a hot day you can wade a long way out and still stand. Mardorf, on the north shore, is the beach side, with a long strip of sand, a promenade and a swimming area, and the water warms up quickly in summer, so it is a pleasant place to cool off after a day in the saddle.
The lake is a favourite playground for sailors from Hannover, and its flat water and steady breeze suit small dinghies and windsurfers. The shallowness also makes it a sanctuary for birds. Reedbeds around the shore hold herons, grebes and many ducks, and the moorland to the north, the Meerbruch nature reserve, is a protected area of bog and wet woodland. The famous local food is smoked eel, taken from the lake and served in the fish restaurants of Mardorf and Steinhude, a tradition that goes back centuries.
On an island in the middle stands the Wilhelmstein, a small fortress built in the eighteenth century by Count Wilhelm of Schaumburg-Lippe, one of the more inventive minds of his age. He built it on an artificial island as a military school and a stronghold for his tiny state, and it was one of the earliest places to train officers in a scientific manner. Small boats run to it from the shore in summer, and a visit is a fine excursion.
The lakeside road is flat and gentle, with long views of water through the trees and a surface that is generally good, though busy on warm weekends when Hannover empties onto the shore. Parking at Mardorf fills early. Cyclists and walkers share the paths and lanes, so ride calmly. Fuel is not abundant right on the shore; Rehburg-Loccum, eight kilometres away, and Hagenburg are better bets for stations and shops.
The water is cool in June and warm by August. A morning swim and a plate of smoked eel make a good midday break, and the sunset over the lake from the western shore is memorable.