A server at my favorite restaurant in Leonidio, a town in the Peloponnese, brings a tray of shot glasses to our table. My friends consume their drinks in one swallow, but I sip mine. It is sweet with a heady, herbal aroma and a light flavor of pine. I have never tasted anything quite like it. This is my introduction to mastiha, a traditional Greek liqueur flavored with mastic, the hardened resin of the mastic tree. Mastic is a little bit of wonder. Thanks to a combination of climate, soil, and careful cultivation, the Greek island of Chios is the only place in the world where the tree exudes its aromatic resin—hence mastic's Greek nickname, "tears of Chios." Raw mastic can be crushed and mixed with salt to flavor savory dishes or with sugar for sweets. Mastic imparts its flavor to Easter and Christmas breads, spoon sweets (jams), and various confections. Today, the resin is experiencing a renaissance of sorts and can be found in gourmet ice creams and fine chocolates. The techniques used to harvest mastic haven't changed much since the days of old. Farmers on Chios carve incisions into the tree and allow the sap to seep onto the bark and eventually harden into droplets that fall to the ground like so many tears.