n which Mr. George indicated; and there he
saw upon the bank of the river, a little below the Custom House, rising
above the other buildings in that quarter of the town, a large, square
edifice, with turrets at the corners. This building was surrounded with
other edifices of a castellated form, which gave the whole the
appearance of an extended fortress.

"That," said Mr. George, "is the famous Tower of London."

"What is it famous for?" said Rollo.

"I can't stop to tell you about it now," said Mr. George. "It was built
originally as a sort of fort to defend the city. You see, the place
where the Tower stands was formerly the lower corner of the city; and
there was a wall, beginning at the Tower, and running back all around
the city, and so down to the water again at the upper end of it. Do you
see St. Paul's?" added Mr. George, turning half round and pointing.

"Yes," said Rollo; "but it is pretty smoky."

"You can see," said Mr. George, "from the position of St. Paul's, where
the old wall went. It passed some distance back from St. Paul's, and
came down to the water some distance above it. All within this wall was
the old city of London; and the Tower was built at the lower corner of
it to defend it.

"Do you see any reason," continued Mr. George, "why they should place
the Tower at the lower end, rather than at the upper end, of the city?"

"No," said Rollo, "I do not see any reason in particular."

"The reason was," said Mr. George, "that what they had reason to guard
the city against was the danger of an attack from enemies coming _up_
the river in ships from the sea; and so they placed the Tower _below_
the city, in order to intercept them. But now the city has spread and
extended down the river far below the Tower, and back far beyond the old
wall; so that the Tower is, at the present time, in the midst of an
immense region of streets and warehouses, and it is no longer of any use
as a fortification. It is too high up."

"What do they use it for, then?" said Rollo.

"It is used by the government," said Mr. George, "as a sort of strong
box, to keep curiosities, treasures, and valuables of all sorts in, and
any thing else, in fact, which they wish to have in safe and secure
custody. They keep what are called state prisoners there."

"Can we go in the Tower," said Rollo, "and see all these things?"

"Yes," said Mr. George, "we can see the treasures and curiosities; but I
believe there are no prisoners