Other viruses that can cause colds include coronavirus, respiratory syncytial virus, influenza and parainfluenza. Colds cause a lot of people to stay home. The CDC says 22 million school days are lost each year in the U.S. because of them. Some estimates say that Americans have 1 billion colds a year. For more detail, see Common Cold Causes. How a Common Cold Starts. You can catch it from another person who is infected with the virus. This can happen by direct physical contact with someone who has a cold, or by touching a surface contaminated with their germs -- like a computer keyboard, doorknob or spoon --- and then touching your nose or mouth.
The hypocaust system. The hypocaust system (hypocaustum in Latin) was a heating system used in (wealthy) Roman homes and Roman baths, and the closest thing to central heating today. The hypocaust was a system that circulated hot air under the floor and surrounding walls. Hypocaust construction
Roman Buildings: The Romans invented an incredible building material called concrete. They used it to build the dome of the Pantheon, which even today is still one of the largest single-span domes in the world.The also used concrete to build the Colosseum, the Circus Maximus, and even an underwater port facility at Caesarea (in Israel).One of the greatest feats of Roman engineers were the Roman roads.hey used it to build the dome of the Pantheon, which even today is still one of the largest single-span domes in the world. The also used concrete to build the Colosseum, the Circus Maximus, and even an underwater port facility at Caesarea (in Israel). One of the greatest feats of Roman engineers were the Roman roads.