St. Michael's Mount (Marazion, near Penzance) - St. Michael's Mount, a castle perched atop a rocky island, was once a Benedictine priory, before that a Celtic monastery, but became a fort, and then private residence of the St. Aubuyn family in the 17th century. Explore the island, climb up to the castle and discover rooms filled with history, armor, and legends, at the top are cannons, ramparts, and stunning views of the Cornish coast.

You can walk with kids to the island at low tide, but you'll need to take the boat at high tide.

Neolithic standing stones - Cornwall has a number of large Neolithic dolmen (upright stones with a capstone) called "quoit." Stop to see the Zennor Quoit near St. Ives, Chûn Quoit and Lanyon Quoit near Penzance.

Poldark Mine and Heritage Complex (Helston) - Take a tour of Poldark Mine, a tin mine in operation since the 1720's. After you've put on a hard hat and crept through the long winding tunnels, point out that children, eight and nine years old, worked the mines along with their mothers and fathers.

Beaches - It the weather is good, there are some fine beaches in Cornwall - sparkling water, sandy beaches for swimming and rocky pools for kids to explore. Perran Sands, Trevaunance Cove, Praa Sands in Helston, Maenporth, Swanpool, Gyllyngvase in Falmouth are family beaches.