What is Oolong tea and Wu-Yi tea?

In Chinese tea culture, Oolong tea is a semi-oxidized tea somewhere between green tea and black tea is oxidation. It ranges from 10% to 70% oxidation. Oolong has a taste more akin to green tea than to black tea: it lacks the rosy, sweet aroma of black tea but it likewise does not have the stridently grassy vegetal notes that typify green tea. There are many Chinese teas can be classified as Oolong tea based on the way of oxidation.

Wu-Yi tea, produced in the Wu-Yi mountains, is the best and the most expensive Oolong tea in the world.