Bread that is unleavened is made without leavening agents, such as yeast or sourdough culture, which allow bread to rise. This type of bread comes with a history of rich religious culture, especially in Jewish and Christian culture. However, it is also a common form of everyday bread eaten on a regular bases in many countries.
During the Jewish Passover, Jews may only eat matzah (or matzo) --- unleavened bread --- in remembrance of the Jewish exodus of Egypt when Jews fled in such haste that they did not have time to allow their bread to rise. To make matzah, according to strict interpretations of the Torah, flour must be protected from moisture and heat prior to mixing to avoid fermentation (this kosher flour is known as Shemurah flour) or whole-grain wheat flour must be used. Tools must be kosher as well, cleaned thoroughly. Cold water is drawn from a spring and allowed to settle in a cool, dark place overnight to assure the water is not warm. Extremely hot temperatures (315 to 426 degrees C) are used to bake the bread, all in an effort to completely avoid the leavening of the bread.
Chapatti is an Indian bread made from dough of atta flour (variations replace atta flour with wheat, corn or gram flour or a combination of flours), water and salt. It is rolled into large discs and browned on a very hot griddle or frying pan. It is then exposed briefly to an open flame, which causes the chapatti to puff up like a balloon. It is commonly brushed with clarified butter.
Tortillas are commonly found in Mexico and Spain and are made from corn flour or wheat flour. A recipe from Abigail's bakery instructs you to mix 2 1/4 cups flour, 1 tsp salt, 1/4 cup lard and 3/4 cup water into a large mixing bowl, turn and knead on a floured surface, then divide the dough into pieces and let rest, covered, for at least 1/2 hour. Flatten and roll the balls into thin patties, then cook over a skillet until lightly browned.
Even pancakes can be considered unleavened bread when no yeast is used to raise the batter. Pancake mixes can be found that only require a couple additional ingredients to make pancake batter. Most pancakes are cooked on a griddle, flipping once when the first side is cooked to cook the other side.