architecture art Ashton balustrade baroque building carving columns concert copper dome dramatic edwardian elevated elevation folly gallery grade granite hall hill historical imposing Lancaster landmark limestone majestic memorial monument one listed Palladian park parkland Portland sculpture skyline staircase steps stone venue Williamson window windows agenda arranged audience auditorium business chair chairs classical conference convention discussion empty entertainment event floor function furniture guest guests lecture marble meeting place prepared private room semi-circle seminar Speaker talk theatre wall walls