Simplify the following text for a Grade 16 native English-speaking person.
Original: Six Tuscan localities have been designated World Heritage Sites : the historic center of Florence ( 1982 ) , the historical center of Siena ( 1995 ) , the square of the Cathedral of Pisa ( 1987 ) , the historical center of San Gimignano ( 1990 ) , the historical center of Pienza ( 1996 ) and the Val d'Orcia ( 2004 ) .
Simplified: Six Tuscan localities have been made UNESCO protected sites : the historical center of Florence ( 1982 ) , the historical center of Siena ( 1995 ) , the square of the Cathedral of Pisa ( 1987 ) , the historical center of San Gimignano ( 1990 ) , the historical center of Pienza ( 1996 ) and the Val d'Orcia ( 2004 ) .