The first stop is the Prince's Palace. Following the winding road up the hillside, we soon saw the magnificent palace built on the cliffs. The oldest building in the city of the Principality of Monaco belongs to this ancient castle. Now there are old cannons on the battlements, and there are watchtowers in every corner of the castle. Now the palace is built on the basis of the old castle. It was built in the 13th century and has a history of several hundred years. It is surrounded by a large stone wall with a pheasant and many black shooting holes. Modern buildings and ancient castles intertwined in front of the palace gate is an open square, rare tourists occasionally show themselves in the open area under the hot sun. Perhaps because it was a military fortress built by Genoans in the 13th century, there were many ancient cannons around the Palace Square. It was funny for such a small country to show off such force. Instead of purchasing tickets to visit the palace, we stood up and watched the overcrowded skyscrapers of the country. At noon, after waiting for about 20 minutes in the Prince's Palace Square under the scorching sun, I grabbed the advantageous position and watched the temporary change ceremony of the Royal Palace Guard. We watched two Shanghai girls who had entered Europe from Barcelona, Spain, and planned to visit for 45 days. I envy them for being so young and promising that they already have the energy to play around the earth.