The tallest spire in Britain
Salisbury Cathedral is located about 10 miles south of Stonehenge. It's worth a visit, and if you visit, definitely take one of the tours offered by the guides. That's the best part.
You'll also be able to see the finest surviving copy of the Magna Carta (originally it's thought there were 44 copies made, written in a shorthand Latin). It's in perfect condition, because it was filed away in a library and only discovered in the 19th century.