Possible Clues:

• It has round walls
• Do a turn, roaming circular building
• Barrel kept in bar, a domed building
• The Pantheon in Rome has one
• Do a turn (anag) — circular domed building
• Decay reported beneath the Pantheon, for example
• Building showing decay beneath, we hear
• Decay, reportedly beneath and round building
• Building over frozen soil sees river rising
• Decay reportedly beneath building