Formally called the Royal Botanic Gardens Kew the gardens are said to have begun in 1759 when Princess Augusta started constructing a 9 acre garden around Kew Palace, though there may well have been some garden around the palace before this. It has now grown to over 300 acres in one of the world’s biggest cities.
Kew is where horticulture and botany overlap and merge. As well as being a stunning garden this is a vast living collection of plants from all around the world many of which reached the west via Kew. If you are looking for to find what a specific plant looks like you can go onto the Kew Gardens website and see if they are growing it and where, alternatively you can trust to serendipity and allow the garden to inspire you.
Although not really a “garden” it is one of the finest living collections of plants in the world and therefore worth several visits by anyone interested in plants.