Shenyang is the biggest city of the Northeast of China. It was once the capital of China about 300 years ago in Qing dynasty. It also was an important city in the war years. If you go there, you could go to visit the resorts like Imperial Palace of Shenyang, the royal catacombs, the mansion of General Zhang, etc. Besides, their folk art is another must-go, it called song-and-dance duet, very famous in China. And the food there also is very good. By train from Beijing just 4 hours.