Follow the Blue Plaque Trail through the centre of Marlborough.
Marlborough College - some interesting buildings, including the chapel, can be seen from the street at the west end of town. The mound is in the grounds - once the site of Marlborough Castle and reputed to be the burial place of Merlin's bones.
The Merchant's House - restored 17th Century silk merchant's house on the High Street - the shop supports the Charitable Trust, and the House and Gardens are open for tours.
Cardinal Wolsey was ordained a priest in St Peter's Church at the west end of the High Street. It closed for worship in 1974 and now houses a cafe, arts and crafts shop, regular music events, tower tours and more.
Out of town:
Avebury - stone circle and manor house.
Crofton Beam Engines - the oldest working steam engines in the world, still doing the job they were designed to do.
Marlborough is in the North Wessex Downs Area of Outstanding Natural Beauty, there's some lovely countryside to explore.
West Woods - peaceful woodland, and a must in mid to late May for carpets of bluebells as far as the eye can see.
Wilton Windmill - a working windmill, still producing flour on certain days of the year.
The North Wessex Downs Area of Outstanding Natural Beauty has an introductory video to give you a taste of the area: https://youtu.be/UjtNri8890o