Kew has famous conservatories. There are 3 large ones, two dating from Victorian times. I can just imagine the great excitement that visits to such conservatories would have generated in late 19th century England. The exotic plants from distant parts of the world could surely fire-up the imagination. The conservatories, naturally, house collections of plants too tender for the London winter (mild as it is). The plants are often arranged by geographic region (Australia, New Zealand, South Africa, North America, the Mediterranean, etc) as well as by environments (temperate areas, deserts, humid tropics, high elevation tropics, grasslands, etc).
The two Victorian conservatories (the Temperate House - pictured above - and the Palm House-pictured in the 99 visit) are also very elegant. The Temperate House holds citrus fruits, tea and the world's largest indoor plant. The tropical Palm House is a Victorian masterpiece with many rainforest species; in the basement there is a Marine display that holds algae, coral and fish. The modern Princess of Wales conservatory (below) has "10 different climates with plants ranging from tiny orchids to the giant waterlily, as well as cacti... and carnivorous plants..."
