The seaport of Portland is Maine’s largest urban area. Perched on Casco Bay, it’s home to many island and coastal communities. During your Portland, Maine vacation, you will find a variety of things to do and see. The city is known as a cultural, dining and shopping destination, but you'll also find walking and biking trails as well as a beach. You can also tour the Portland Observatory—the only remaining historic signal tower in the nation—or take a Great Portland Landmarks self-guided walking tour of Portland's four major historic districts.