Silphium was the wonder plant of the ancient world. Originally identified by Greek colonists in North Africa, the plant - a species of Fennel (Foeniculum vulgare) - grew only in a dimunitive area near the coast and could not be cultivated. Silphium was popular as a spice for cooking, but its notoriety stems from its alleged medicinal qualities, particularly its use as an herbal contraceptive (the "I love you" heart symbol may have originated from the shape of silphium's seed pods and its use in sex). So valuable was Silphium that it became an important component of the ancient world's economy and appears on coins. It's also among the first species recorded (by Pliny the Elder) as going extinct, probably by grazing sheep or uncontrolled harvesting. Or is it?