Royal Botanic Garden Edinburgh

This guide to the Royal Botanic Garden Edinburgh explains the strange brief behind its great stone palm house: blocking out the sun, an odd goal for a greenhouse meant to grow tropical plants. You'll hear how curator James McNab pushed back against the fashionable iron-and-glass style of the 1850s, arguing it lost heat too fast, and how architect Robert Matheson agreed to build almost entirely from sandstone hauled from a quarry near Glasgow. It follows a Victorian bet that mass beats glass for holding warmth.