The Pantheon or Dome (1960-61, listed Grade II, 1971) is an octagonal building surmounted by a dome and central octagonal cupola. During the late 1950s Clough felt the village suffered from 'dome deficiency' and decided to remedy this. The foundation stone was laid by Earl Russell O.M. and the Pantheon or Dome was completed during 1961. For its ornate gothic porch he used a vast Norman Shaw fireplace of red Runcorn sandstone from Dawpool, Cheshire which he had acquired 20 years previously. This had been in situ in its present position since 1957, then known as The High Cloister. The Dome's supporting walls were built by April 1959 leaving only the actual dome itself. "'In the matter of the dome and its lantern," he wrote, "I just gave [Mr Braund-Smith, the master-joiner] the outside silhouette of what I wanted and left him to puzzle out its actual construction: a challenge met with an economy and elegance that is in itself a pleasure to behold." As the Dome reached completion and the ball was finally fixed on top of its lantern, Clough could be seen high up a ladder (he was nearing eighty at the time) laying on the gold leaf. The Pantheon with its dome and lantern is assumed by many to be a temple and Clough was often under pressure to make it over for such use but as his own position was an impartially yet firmly neutral one he foresaw its future as probably secular. Perhaps in part due to this refusal, the Church in Wales refused permission for Clough's memorial plaque to hang in the old church in Llanfrothen. It is now respectfully displayed in the Pantheon. There are several other interesting items on show here such as the old tollgate sign and his model for the Chantry.
Hans Feibusch's cartoon The New Arrival, made to mark Clough's knighthood in the 1972 New Year's Honours hangs in the Dome.
Sir Christopher Wren, Sir Nicholas Hawksmoor and Sir John Vanbrugh are quizzing the latest arrival, Sir Clough. WREN: He says that he reveres our works and shares our principles and so claims that he too should be counted an Architect - in spite of his aberrations. How say you both? HAWKSMOOR: (Dubiously)...Well... VANBRUGH: (Dubiously)...Um...