Simplify the following text for a Grade 10 native English-speaking person.
Original: In 1996 , UNESCO declared the town a World Heritage Site , and in 2004 the entire valley , the Val d'Orcia , was included on the list of UNESCO 's World Cultural Landscapes .
Simplified: In 1996 , UNESCO put the town his list as a World Heritage Site , and in 2004 the all valley , the Val d'Orcia , was put on the list of UNESCO 's World Cultural Landscapes .