It's worth the whole trip. I strongly recommend
In Beijing, this is a famous spot which offers a lot to see, espicially in terms of history and achitecture. Keep in mind that when you arrive here, your passport is important as it serves a ticket to enter the Forbbiden City and other places around Tian An Men Square.
Is it such a great place to visit in Beijing, especially watching the flag raising and flag lowering make you have higher respect for China. The flag raising early in the morning and flag lowering in the afternoon are such a must-activity to experience when in Tiananmen.
Chang'an Street, Dongcheng District, Beijing (between Tiananmen and Zhengyangmen)