sentences:  There are 129 ancient yews with a girth over 3.5m (over approx 500 years old) with some over 6m girth (probably at least 1000 years old) on the northern wooded slope.Some trees are so old the centre is hollow and the whole tree can be walked through.Newlands Corner was a key location in the crime writer Agatha Christie's disappearance in December 1926.