The little business she started by herself has now become a 'mammoth' [='giant'] in the industry.
Renovating the house is a 'mammoth' undertaking.
a 'mammoth' [='huge, gigantic'] building
(..) I saw an iceberg once. They were hauling it down to Texas for drinking water. They didn't count on there being an elephant frozen inside. - The woolly kind. A mammoth. - Dad! What? I'm trying to make a metaphor here. Well, you shouldn't have started with a question... (..)2003 Big Fish