In my tours of North Korea, China and more specifically Dandong, it was expressed by several Chinese people that the Chinese sided with North Korea in the Korean War because they were Communist brothers and they were geographical neighbors. However, all the people I spoke to stated that even though they fought with the North, Chinese opinion and general belief is that North Korea started the civil war and was the aggressor.
Also, in all the museums of China, the impression is made that the 2.9 million Chinese soldiers fought side by side the North Koreans. Many died, more were wounded. However, in all my time in North Korea, no mention of the Chinese armies was ever voiced. On the contrary, it was not with the aid of 2.9 million Chinese soldiers that the Allied/UN forces signed an Armistice at Panmunjom, but rather it was Kim il-Sung who single handledly defeated the US. (and the Japanese in WWII also).
Having visited both China and DPRK, the photo on my Dandong page and this photo I believe give the best visual impression of the disparities between the two countries.
I've commented within my North Korean pages how dissimilar the two Korean countries are, but the comparison between the bustling Chinese cities and the quiet expanses of North Korea are numerous as well.
During the day time, you can see the occasional North Korean worker, farmer, boat or other doing their daily routine. But the movement is rare and always fairly quiet. The Chinese side on the other hand is a loud, bustling city, full of cars, people, tourists, shopping, and everything that our minds can think of.
At night, China is a glow with lights and the sounds of people, festivities and life. The other side of the Yalu river is a dark, invisible land that might as well be a void looking over the expanses of an ocean.
This photo was also taken from aboard a Chinese speedboat in North Korea's territorial waters on the Yalu River. You can see the "Short Bridge" in the foreground. The "Friendship Bridge" can support both trucks and trains but pedestrian traffic is not allowed.
Fondest memory: The Yalu River Bridge Park is on either side of the Friendship Bridge. There are a couple of gift shops selling North Korean stamps and currency. This is also the place where you can hire the Chinese speedboats to take you across the Yalu River for a brief jaunt and taunt of the North Korean coastal population.
One of the highlights of a visit to Dandong is taking a Chinese speedboat across the Yalu River to get a close-up view of North Korea.
Here is a photo I took after I asked the speedboat driver to get closer to this North Korean ship moored next to the shore at Sinuiji.
Fondest memory: The speedboats travel along a predetermined route west of the bridge. They will not stop at the North Korean shore but you do get close enough to take photos and they will slow the boat down as long as you don't taunt any North Korean dock workers who resent the daily harassment by tourists.
One of my favorite things about Dandong is the view of North Korea across the river. The city of Sinuiji is within shouting distance if you go out to the end of the short bridge and do your best loud rendition of "Arirang"
Fondest memory: There appears to be an amusement park at the end of the bridge in North Korea but Dandong locals who work at the short bridge gift shop tell me that they have not seen the big wheel turn for a long long time.
There are one and a half bridges over the Yalu River in Dandong. The half bridge is called "Short Bridge" due to the fact that it was bombed by American planes during the Korean War. By using the free binoculars provided at the end of the short bridge you can look across to North Korea and get a closer look at this school.
Fondest memory: This photo was taken from one of the speedboats which are available for short rides across the Yalu River west along the North Korean territorial waters.