<P> The main building material is Kentish rag - stone , although some local mudstone was also used . Caen stone was imported from northern France to provide details in the Tower 's facing , although little of the original material survives as it was replaced with Portland stone in the 17th and 18th centuries . As most of the Tower 's windows were enlarged in the 18th century , only two original -- albeit restored -- examples remain , in the south wall at the gallery level . </P>
<P> The main building material is Kentish rag - stone , although some local mudstone was also used . Caen stone was imported from northern France to provide details in the Tower 's facing , although little of the original material survives as it was replaced with Portland stone in the 17th and 18th centuries . As most of the Tower 's windows were enlarged in the 18th century , only two original -- albeit restored -- examples remain , in the south wall at the gallery level . </P>
where did the stone for the tower of london come from
where did the stone for the tower of london come from
Kentish northern France
Kentish northern France