Viruses cause a number of diseases in eukaryotes. In humans, smallpox, the common cold, chickenpox, influenza, shingles, herpes, polio, rabies, Ebola, hanta fever, and AIDS are examples of viral diseases.Even some types of cancer -- though definitely not all -- have been linked to viruses.n humans, smallpox, the common cold, chickenpox, influenza, shingles, herpes, polio, rabies, Ebola, hanta fever, and AIDS are examples of viral diseases. Even some types of cancer -- though definitely not all -- have been linked to viruses.
Map of the fortifications. Located in Canada, the Ramparts of Quebec City are the only remaining fortified city walls in North America north of Mexico. The British began refortifying the existing walls, after they took Quebec City from the French in the Battle of the Plains of Abraham in 1759.
Located at a commanding position on cliffs overlooking the St. Lawrence Seaway, Quebec City's Old Town is an UNESCO World Heritage Site and the only city in North America (outside Mexico and the Caribbean) with its original city walls. Quebec is a city of about 700,000 residents.