"Great" most often evokes power and respect. In informal English it's almost always positive but in formal contexts it can be used simply to describe the enormity or power the object or person has. "David helped me get the job. He is a great man!" "The great Martin Luther King Jr. inspired many to join the civil rights movement." "Santa Fe is a great city full of many opportunities." "The great emperor declared war on the neighboring countries." "My teacher is great because she explains everything so well." Most often we find, "great" is used to describe abstract qualities of a person or place. We don't usually use "great" to describe big physical features. "Huge" can definitely be used to describe physical features that are big. It can also describe historical and current events (of big proportions of course). "The dog is huge. It weighs at least 70 pounds!" "The city of Los Ángeles is huge." "The Beatles had a huge influence on the youth." Hopefully this helps! :)