Temple of Friendship

The Survey reports that building on the Temple of Friendship was begun as early as 1737, assuming that work listed in accounts for that year on a Temple of Diana set on Diana's Bastion refers to the Temple of Friendship. The building was designed by James Gibbs, who was responsible for most of the buildings in Hawkwell Field and who was called back to Stowe as architectural designer after William Kent left around 1736. Gibbs' final design, as reported by Bevington, was for a central room flanked on the east and west by two loggias. The building is fronted by a Tuscan portico, and in 1772-74 the core and roof of the building were heightened, perhaps to match the growth of the surrounding trees, but certainly to provide a larger silhouette to catch the eye from other viewpoints in the field.
Inscribed on the exterior of the building is AMICITIAE S (sacred to friendship), and inside were placed busts in white marble of Lord Cobham and nine of his friends: Earl Bathurst, the Earl of Chatham, the Earl of Chesterfield, Earl Gower, the Earl of Marchmont, Earl Temple, the Earl of Westmoreland, Lord Lyttleton, and Frederick, Prince of Wales. (Three of these men were Cobham's nephews: his heir Richard Grenville, later Earl Temple; William Pitt, later Earl of Chatham; and Sir George Lyttelton.) On the ceiling was a painting of Britannia surrounded by other figures, one of which held a label with the words "The Reign of King Edward III," another of which held a scroll with the words "The Reign of Queen Elizabeth," and a third holding a scroll with the incomplete title "The Reign of ------" which was covered by Britannia's mantle and which she seemed unwilling to look at.
Views from the portico include the Temple of Ancient Virtue in the Elysian fields to the northwest, the Queen's Temple at the far end of Hawkwell Field, and Lord Cobham's Monument, the Gothic Temple, and the Palladian Bridge along the east side. From the windows in the rear of the central room the Corinthian Arch can be seen, and at a time before the view was obscured by planting, the Temple of Venus could be seen on Kent's Bastion to the west. A fire in the early nineteenth century rendered the building an empty shell, and parts of it in danger of falling were demolished in 1884. Today the Temple has the feeling of a romantic ruin.
faculty.bsc.edu/jtatter/friends.html

From here it is not far to the Palladian Bridge.