Why were the roman buildings so big?

Roman buildings were constructed on a grand scale to demonstrate the power, wealth, and engineering prowess of the Roman Empire. The use of innovative architectural techniques, such as the arch, vault, and concrete, allowed for larger and more durable structures. Additionally, large buildings served public functions, such as forums, basilicas, and amphitheaters, which reflected the social and political life of the time. These monumental designs also aimed to inspire awe and convey the empire's greatness to both citizens and visitors.