See Vauban, just outside of Freiburg. The town is considered to be the most sustainable city in the world. This walking tour is an introductory tour of the town and will include stops at some of the ongoing projects to show visitors how citizens are working to keep town "green".

The Solar Estate is home to some of the most up-to-date solar-home technologies in the world. At the Solar Estate, see the Plusenergiehaus®. A dynamically engineered solar home that generates more energy that it consumes, the Plusenergiehaus® sells its excess power back to the public power grid—at a profit of more than 5000 Euros a year.

Guten tag and bonjour. The capital of Alsace-Lorraine, Strasbourg embodies the best of the German and French cultures once battling to control the area. Join a local licensed guide for a walking tour of Petite France, Strasbourg’s medieval quarter. The magnificently Gothic Notre Dame cathedral is the city’s spiritual center, while in the adjoining square the elaborately carved Maison Kammerzell, once a wealthy merchant’s house, gives evidence of Strasbourg’s healthy economic history.

Although construction began in the 11th century, this cathedral was completed in 1439. This sandstone structure is a combination of Romanesque (the choir) and Gothic (the nave) architecture.

This city was made for walking. Stroll grand boulevards with sweeping views of the city, pristine parks with trees planted in perfect rows, and narrow streets crowded with vendors selling flowers, pastries and cheese. Then head to the Île de la Cité, a small island in the Seine, to see Notre Dame Cathedral. Please note Notre Dame Cathedral is currently closed due to fire damage.

View the Notre-Dame Cathedral. Work began in 1163 on a spot that had been a holy shrine since Roman times. Over the centuries, the cathedral has been the scene of some of France's most momentous occasions, including the coronation of Napoleon.

What's that huge white arch at the end of the Champs-Élysées? The Arc de Triomphe, commissioned by Napoleon in 1806 after his victory at Austerlitz. Your licensed local guide will elaborate on this, and other Parisian landmarks. See some of the most famous sites, including the ornate, 19th-century Opera, the Presidential residence, the ultra-chic shops of the Rue du Faubourg St-Honoré, and the gardens of the Tuileries. You'll pass the Place de la Concorde, where in the center you’ll find the Obelisk of Luxor, a gift from Egypt in 1836, and the Place Vendôme, a huge square surrounded by 17th-century buildings. Spot chic locals (and tons of tourists) strolling the Champs-Élysées. Look up at the iron girders of the Eiffel Tower, built for the 1889 World's Fair to commemorate the centenary of the French Revolution. See Les Invalides (a refuge for war wounded), the École Militaire (Napoleon's alma mater), and the Conciergerie (the prison where Marie Antoinette was kept during the French Revolution).

Tuileries was originally the name of an old tiles factory. Yet, in the sixteen century, the queen of France, Marie de Medicis, ordered to build a castle with a long French garden at this place. Parisians used to call this new building the Tuileries Palace. During three centuries the garden was exclusively reserved for the court and the King. During the nineteen century, the Tuileries palace became the residence of Napoleon I, Louis XVIII, Charles X, Louis-Phillipe and Napoleon III. In 1871, Parisians burnt down the castle of Tuileries, during the last French Revolution and the insurrection of Paris.However, the garden kept its 17th-century design and became a popular place, always crowded in summer time.

The world's largest art museum, the Louvre is housed in a Medieval fortress-turned-castle so grand it's worth a tour itself. You walk through the 71-foot glass pyramid designed by I.M. Pei and added in 1989, and step into another world--one with carved ceilings, deep-set windows, and so many architectural details you could spend a week just admiring the rooms. The Mona Lisa is here, as well as the Venus de Milo and Winged Victory (the headless statue, circa 200 BC, discovered at Samothrace). The Louvre has seven different departments of paintings, prints, drawings, sculptures and antiquities. Don't miss the Egyptian collection, complete with creepy sarcophagi, or the collection of Greek ceramics, one of the largest in the world. (Please note the Louvre is closed on Tuesdays.)

The curious have been touring the Paris sewers since the 1850’s. Visit what Victor Hugo called the Paris below Paris, “…a Paris of sewers; which has its streets, its crossings, its squares, its blind alleys, its arteries, and its circulation, which is slime, minus the human form." Experience the Paris Sewers Museum, which is located beneath the Quai d’Orsay on the Left Bank, is a popular destination for anyone interested in how a major metropolitan city manages its waste and water recycling.

Your Tour Director will lead this educational two-hour math and science treasure hunt through the Latin Quarter of Paris. Students divided into teams will find clues tied into the city's history.

See the city from the water on an hour-long cruise along the River Seine. The Seine cuts right through Paris, dividing the city in half. See the Eiffel tower rising up on the Left Bank, the walls of the Louvre on the Right Bank. A guide will point out other monuments and architectural marvels as you pass, many of which are illuminated by clear white light at night.

Step into the world of science, technology and discovery! The Cité des Sciences et de l’Industrie is dedicated to spreading scientific and technology using demonstrations, experimentation and manipulation to make science accessible to everyone.

If you’re coming to Paris, you absolutely need to take a walk in Montmartre! This area will wake the artist in you up. Its narrow alleys, windmills, little details, and soul are some of the things that make Montmartre so unique. As you walk in Montmartre, you will quickly understand how it has inspired so many artists such as Picasso and Van Gogh. As you walk up the hill make sure to take in all that surrounds you, because in Montmartre you are likely to find surprises around every corner!