Which sentence best reveals the author's purpose in paragraph 1?
from CHAPTER XIV of The Innocents Abroad
by Mark Twain
At Pisa we climbed up to the top of the strangest structure the world has any knowledge of-the Leaning Tower. As everyone knows, it is in
the neighborhood of one hundred and eighty feet high--and I beg to observe that one hundred and eighty feet reach to about the height of four
ordinary three-story buildings piled one on top of the other, and is a very considerable altitude for a tower of uniform thickness to aspire to,
even when it stands upright-yet this one leans more than thirteen feet out of the perpendicular. It is seven hundred years old, but neither
history or tradition say whether it was built as it is purposely, or whether one of its sides has settled. There is no record that it ever stood
straight up. It is built of marble. It is an airy and a beautiful structure, and each of its eight stories is encircled by fluted columns, some of marble
and some of granite, with Corinthian capitals that were handsome when they were new. It is a bell tower, and in its top hangs a chime of ancient
bells. The winding staircase within is dark, but one always knows which side of the tower he is on because of his naturally gravitating from one
side to the other of the staircase with the rise or dip of the tower. Some of the stone steps are foot-worn only on one end; others only on the
other end; others only in the middle. To look down into the tower from the top is like looking down into a tilted well. A rope that hangs from the
center of the top touches the wall before it reaches the bottom. Standing on the summit, one does not feel altogether comfortable when he
looks down from the high side; but to crawl on your breast to the verge on the lower side and try to stretch your neck out far enough to see the
base of the tower, makes your flesh creep, and convinces you for a single moment in spite of all your philosophy, that the building is falling