Truffles

A truffle is a rare, edible mushroom that is considered a delicacy in many parts of the world. Generally harvested in the wild, they are quite expensive. Truffles are often confused with chocolate-covered truffles, a confectionery that has no relation to mushroom truffles.
Requiring climates with mild weather changes, truffles grow in a limited number of places including France, Italy, Croatia, and Slovenia. Truffles are also collected in the United States, in states like Oregon and Washington, as well as parts of the Middle East, North Africa and New Zealand. 

They grow approximately one foot (30 cm) underground among the roots of oak, elm, chestnut, pine, and willow trees where they form a symbiotic relationship with the environment.
There are dozens of different types of truffles ranging in size from a walnut to an apple. Truffles are irregularly-shaped with sometimes smooth, though usually bumpy or wrinkled caps.

Truffle hunting is big business during truffle season, which generally lasts from fall to spring. Each year, trufficulteurs use specially-trained dogs that find the buried treasures, usually at night. In the past, female pigs or sows were used to hunt for truffles, as the pungent odor that the truffles emit is similar to that of a male pig. The sows were difficult to hold back once the truffle was located, however, and would readily consume the expensive delicacy. For this reason most hunters now use truffle dogs.

The taste of a truffle is often compared to garlic blended with an earthiness or pungent, mushroomy flavor. They are most often served uncooked and shaved into foods like pasta, salads, or omelets. They are also served in light sauces, on fondue, or even on pizza.
Of the many varieties of truffles, some of the most famous are the Italian white truffle, the French black truffle, the summer black truffle, and the March truffle. The white truffle, often referred to as the white diamond, is considered the rarest type of truffle, demanding one of the highest prices. In general, truffles are among the most expensive natural foods in the world, selling for hundreds or thousands of US Dollars (USD) per pound (0.45 kg).