Simplify the following text for a Grade 11 native English-speaking person.
Original: The district of Bolsover is notable for three sites of historical importance : Bolsover Castle , Creswell Crags ( home to Britain 's only known Palaeolithic cave art ) and Creswell Model Village , an example of early twentieth century design from the Model village movement .
Simplified: The district of Bolsover is notable for three sites of historical importance : Bolsover Castle , the cave art at Creswell Crags and the houses of Creswell Model Village .