This event, including a visit to the Pentagon, is actually one of the reasons that attracted me to travel to the eastern part of the United States. The Pentagon is located in Arlington County, Virginia, not far from DC. The command center, which was set up over a year after the Pearl Harbor Incident of World War II in response to the war, has gradually become the Department of Defense of the United States and the mysterious power center in many movies and TV dramas. This opportunity to enter this mysterious place, in fact, the Pentagon is open to visitors, but must be booked and approved. When the appointed day arrives and passes the security check, the visitor enters the waiting area. The whole process can only be photographed in the waiting area. A mock-up platform is set up here for visitors to remember, as well as souvenir shops. Later, you will be visited by men and women soldiers from both sea and land. A special tour route will be set up. The focus will be on the history of the four U.S. military services. The memorial to General Eisenhower and the memory of 184 people killed in the 911 attack on the Pentagon will be seen, including one passenger and crew member on United Airlines Flight 77. A special memorial facility was set up in the building, with words and pictures recording the lives of each deceased person. Soldiers who lead tourists walk in front of the team and backward to ensure they are always facing tourists. There are many restaurants and shops in the building to meet the needs of more than 20,000 staff members every day.