Beautiful city of almost 30 million people. Happened to be here on a rare stretch of clear days in 2013. Absolutely stunning and easily the most fascinating place I've yet been. Been back again in 2017 and 18 and amazed to see how much has changed!
I spent 13 months living in Beijing teaching ESL to kids. I loved it, the local population (all 20 million of them) are kind. Make sure to try jian bing (if you're vegetarian "wo bu yao ro" will be your best friend), visit the Mutianyu section of the Great Wall, and wander through Wanfujing. I loved visiting the Temple of Heaven, and Lama Temple. Beijing's subway system is easy to navigate and inexpensive, you'll need to bargain with taxi drivers most of the time.
Although I hated the pollution and massification, I felt it was a very special place. Full of art, and tradition it felt like a very good visit (maybe one of the best in my stay in China).
Beijing is a big and great city. Although the API is not so good, but there are many historical places here such as The Great Wall, Tiananmen Square, Forbidden City and Yuhe Yuan etc. Beijing has many famous spot like Olympic Stadium, I heard my sons said got 32 or 36 spots, but we spent there 5 days , so cant visit all, only choose some of popular places.