Over this entrance looms the beautiful tower containing Great Tom, an old, old bell that tolls a curfew of one hundred and one strokes every night as a signal for the closing of the college. And Great Tom looks down on one of those quadrangles which at Christ Church, as indeed at all the colleges, forms one of the most attractive features. In many cases the walls of the buildings which surround the quadrangles on the four sides are almost hid beneath a luxurious growth of English ivy, while from April to December the lawns that carpet them are green with the wonderful depth of color peculiar to lawns that have been cultivated for centuries.