The Eden Project
The Tudor Estate at Cotehele
You will find this in Historic Plymouth along with other intersting sites, such as Plymouth Hoe and the Barbican.
The Lost Gardens of Heligan
The National Marine Aquarium
St Mellion International Championship Golf Course
(This is where the English Open will be held for the next 6yrs. It is only 4 miles away and you will find other golf courses nearby).