Вальдзее: Немецкий языковой лагерь и культурный центр в Миннесоте.

Waldsee ("Lake of the Woods") is the German immersion program offered by Concordia Language Villages. Located near Bemidji, Minnesota, Waldsee is also the site of North America's first certified passive house, which uses 85% less energy than a house built to the Minnesota Energy Code. Waldsee is America's oldest and largest immersion program for German language and culture. Over 1,550 young people participate yearly, coming together from all 50 of the United States and many foreign countries. In 2009 Waldsee was recognized as a U. S. National Center of Excellence for its cultural immersion program by the American Association of Teachers of German.

Waldsee was the brainchild of professors Gerald Haukebo and Erhard Friedrichsmeyer at Concordia College in Moorhead, Minnesota, USA. In 1961, the first two week session of "Camp Waldsee" was held for 72 villagers.

Waldsee offers programs that serve youth (7–18 years old), families of all ages, and adults; one of the high school credit programs travels abroad. During the academic year, Waldsee also hosts school groups. The Waldsee credit program offers traditional instruction as well as credit programs in environmental learning and German (die Gruene Welle) and in medieval history and theater (der Maerchenwald). In the German apprentice program, starting in 2010, participants work half time in the village stores, in gardening and green roof maintenance, music, the arts and the kitchen and bakery, and also learn half time in intensive German language groups. Waldsee's non credit programs include programs that focus on producing FM radio broadcasts at a live radio station, learning about Swiss culture in tandem with the nearby French village Lac du Bois and the Italian village Lago del Bosco, learning about the environment, performing improvisational theater based on medieval lore and legends, and exploring German grammar in depth. Villagers can choose different activities every day. Waldsee offers a wide range of European sports from soccer to fencing. There is also traditional American camp activities such as swimming and canoeing at the beach. Waldsee also has a few giant chess sets and a giant Mühle (nine men's morris) game.

Waldsee is currently located at a culturally authentic site on Turtle River Lake north of Bemidji, Minnesota. Since its founding in 1961, Waldsee has also leased numerous sites across Minnesota. It also offers a credit program that travels abroad.

The Waldsee permanent site, which opened in 1982, is located at near Bemidji, Minnesota on Turtle River Lake, along with six other Concordia Language Village sites. In all, Waldsee can house up to 240 people (typically, there are about 170 students and 40 50 counselors). The site is styled after a typical German village and is centered around a Marktplatz, which is the center of most activity at Waldsee. The Bahnhof is a large building near the entrance of the village that houses class and administrative rooms. The Gasthof is another building that serves as a dining hall and houses most indoor activities. There is an artists' colony, named Worpswede, which has about 6 small cabins and houses the arts and crafts activities. The first building on the campsite was "Haus Katja", which is a log cabin that was built by a group of villagers. The first professionally built building was the Schwarzwaldhaus or Black Forest house, which can house 64 people in four units as well as several more in separate sleeping rooms on the first floor. A twin to the Schwarzwaldhaus is the Max Kade Haus, which was built a few years after the SWH and is very similar in design. Two new medium sized residences have been recently built. The Erich Markel Haus (Oberammergau and Unterammergau) has room for 24 people in two units. The Robert Bosch Haus houses the healthcare center (Heilbronn) and another residence (Stuttgart). The newest building at Waldsee is the BioHaus, the first certified passive house in North America. The BioHaus is an integrated environmental learning center and residence for up to 30 people, including a small apartment upstairs. There is also Café Einbeck, where villagers can sample candy, soft drinks, and other foods from Europe or listen to a jukebox playing German language music. Waldsee also has a Laden at which villagers can make purchases using Euro.

Waldsee has also operated at leased sites since its founding in 1961. Waldsee has been located in Alexandria, Minnesota, Vergas, Minnesota, Menagha, Minnesota, Hackensack, Minnesota, and Cass Lake, Minnesota. Waldsee departed from Vergas in the summer of 2006 to make room for Al Wāḥa, the Arabic language village, which was founded that year.

Waldsee travels abroad to Germany, Austria, and Switzerland with smaller groups of high school students studying German in their summer for credit.

In 2006, Waldsee opened the BioHaus, the first certified passive house in North America, on its permanent site near Bemidji, Minnesota. It is built to the German passive house standard for energy conservation and renewable energy use, and uses 85% less energy than a house built to the Minnesota Energy Code. In 2007, the BioHaus won the Minnesota Environmental Initiative Award in the category of Air Quality and Climate Protection. It was a 2007 Nominee for the World Clean Energy Award in the construction category.

The fixtures are German, and the house helps to introduce students to the "new Germany" as well as preparing them for responsible and ecological citizenship in the global community, the mission of Concordia Language Villages. The modern house itself pays homage to the Bauhaus school of 1920s architecture, and floor to ceiling windows recall the symbolic transparency built into West German government buildings post World War II.

The house was built using eight critical design strategies: Passive Solar Design, Superinsulation, Advanced Window Technology, Airtightness, Ventilation, Space Heating, Efficient Lighting and Electrical appliances. The building replaces 100% outside air; no air is recirculated through the system. Two underground tubes exchange outside and inside air eight feet beneath the ground, passively warming or cooling the air to match the temperature of the ground (~55 °F year round). The house transfers heat between the outgoing air and the incoming air before it reaches the rooms, resulting in a difference of less than 10 °F between the incoming fresh air and the desired room temperature, even in the midst of Minnesotan winter. Water in the house is heated by solar thermal heat panels on the roof, rather than photovoltaic solar cells, which would convert solar energy directly to electricity. Low growing plants make up the building's green roof, reducing rainwater runoff and adding another layer of insulation to the building. Additionally, the western half of the lower level of the structure is tucked into the slope, enabling natural insulation based on the soil.