The Eiffel Tower in an iron lattice tower on the Champ de Mars in Paris, the capital of France. It was built in 1899 for the World Exhibition and meant to be only a temporary structure. However, it soon became a symbol of the City of Lights and a huge tourist attraction, and it still stands today. The tower is 1,063 feet tall and was designed by Gustave Eiffel, known for his revolutionary bridge building techniques. Visitors can go up the tower to one of three levels, either by stairs or by elevator. It can be built using Popsicle sticks painted silver and held together by glue. A piece of cardboard is used for each level and a cocktail stick as the spike at the top.
The Sydney Opera House is Australia's most famous building. It was designed by Danish architect Jorn Utzon and opened by the nation's Queen Elizabeth II in 1973. The building is used for performances and shows, and is opposite the equally spectacular Sydney Harbour Bridge. It's 660 feet in length and 394 feet in width at its widest point. Thick white card, cut into triangular shapes and then curled over, is used for the roof of the model, with the base made out of cardboard.
The Coliseum is an amphitheater originally used for gladiatorial contests and public spectacles in Rome. Although the building is crumbling in parts and under continual restoration, it remains one of the most impressive buildings constructed during the Roman Empire. You'll have to decide on what you condition your model will be -- will you represent the building in its glory or in its deteriorated state? Either way, you'll need to use Styrofoam that is shaped using a knife and held together with glue.
Located on Liberty Island in New York Harbor, the Statue of Liberty is a sculpture donated by France to the United States. It was designed by Frederic Bartholdi and is of a robed character representing Libertas, the Roman goddess of freedom. Visitors typically take a boat trip around the statue before going inside. Because of the statue's intricate shape, the best material to use is modeling clay. The small details can be added as separate pieces, and the design work can be etched in with a sharp knife.
Big Ben is the bell of the clock at the north side of the Palace of Westminster in London, but typically the name is used to refer to the entire tower. It's on the banks of the River Thames, and is famous for tourists waiting nearby to hear it ring. It was first used in 1859 and is 318 feet high. Its rectangular design means it's easy to build. You can simply paint a box of the appropriate dimensions as the main section, with four pieces of cardboard glued together to form a triangle as the roof. The clock face and other details can be drawn or painted on.