The Roman army consisted of 30 legions divided into cohorts of infantry and cavalry troops. Legionaries and auxiliaries wore armor and carried shields, swords, and javelins, often fighting in tightly packed lines using formations like the tortoise shell. Roman towns were built with stone, brick, and tile houses arranged around roads and public buildings like baths and amphitheaters, while Britain had a wild landscape of forests and hills with round wooden homes when the Romans arrived.