Ginkgo biloba is a tall tree, reaching up to 35m, native to China. It is very hardy and fast-growing. It anchors itself with a deep taproot which makes it resilient against drought and high winds. It is considered to be an excellent choice for urban gardens, as you don't really have to worry about any pests, diseases or insect damage.
Ginkgo has been cultivated and valued by the Chinese for fifteen centuries. For whatever reason, it is considered a symbol of the majesty of both the Chinese nation and the Japanese tea ceremony.
The seeds are edible and traditionally said to have adaptogenic, stimulant and aphrodisiac qualities, which science is starting to validate. Ginkgo appears to improve circulation and help dementia, cognitive performance and concetration. See the Wikipedia article for more on this: http://en.wikipedia.org/wiki/Ginkgo_biloba