On the Xian Wall

Xian has a wall that surrounds the ancient city. Our guide says if you
want to visit the upcoming city and see 200 years if history you visit
Shanghai; if you want to see 2,000 years of history you visit NanJing
and if you want to see 5,000 years of history you visit Xian. This is
a very old wall and what you are seeing is the walkway on top of the
wall; it is about 50 ft across. There are 98 guard towers along the
wall.