Birkat HaMazon, what blessing is said before bread? And after?

Birkat HaMazon is the most extensive of all after-blessings. Before eating bread we say 'HaMotzi lechem min ha'aretz': 'Who brings forth bread from the earth.' After eating bread (at least a kezayit, about 28g), we recite the full Grace After Meals, which consists of four blessings: (1) Birkat HaZan: thanking God for providing food to all living creatures, (2) Birkat Ha'Aretz, thanking God for the Land of Israel, (3) Boneh Yerushalayim, praying for the rebuilding of Jerusalem, and (4) HaTov VeHaMetiv, praising God's goodness. The first three are from the Torah; the fourth was added by the rabbis.