Tresco, Isles of Scilly Cruise Port

• The gorgeous and subtropical Tresco Abbey Garden was originally a private garden, established by was established by Augustus Smith, the proprietor of the islands during the 19th century. It miraculously hosts a plethora of exotic plants that would never survive even 30 miles away on the mainland. Along with the plants, you can check out the onsite Valhalla Museum, featuring a collection of shipwrecked figureheads.
   
• The 17th-century Cromwell's Castle was built as a fortification and expanded in 1739 during the Britain-Spain conflict called War of Jenkins' Ear. Today it "guards" the anchorage between Bryher and Tresco; it's one of the last surviving Cromwellian fortifications in the UK. Getting there is lovely in itself, as the path lets you wander through a hillside of heather.
   
• For art, head to the New Grimsby shore to visit Gallery Tresco. The converted boatshed displays exhibitions for both established and new painters (many of them local), along with sculpture, pottery, glass, and jewelry.
   
• For a break to gaze at the sea, visit Rushy Porth Beach. Overlooked by a 16th-century blockhouse, this white sand beach slopes up into dunes and provides panoramic views of St. Helen's and Tean.