In 1752, the Earl of Bute and Princess Augusta of Saxe-Gotha called gardener John Dillman in for a little chat. Their instructions to Dillman were simple: Design a garden. It should, of course, be attractive; a classical English garden, blending the formal decorative with the new fad of naturalism, which is to say, lots of bluebell woods and wildflower meadows.

Oh, and one more thing: The garden should also, in Bute's words: "Contain all the plants known on Earth."

A tall order, but Dillman was unfazed. He got to work. And what are now the Royal Botanic Gardens of Kew, in southwest London, began to grow.