I was born in Beijing, I was raised in Beijing, and now, unfortunately, I spend much of my time away from Beijing. I'm a 2nd generation Beijinger and while I take pride in Beijing being my hometown, like a lot of people in this situation, I still maintain strong ties to a place other than Beijing. My grandparents are both originally from Dongbei (the northeast), Harbin to be exact, and they came to Beijing around the time of Liberation. The Beijing they came to looked a bit like this (taken from the site of the Beijing Cultural Heritage Protection Center, something well worth checking out):
Do you see that thing around the city? That isn't one of the ring roads, that's the city wall. Those things around the outside of the wall? Those are gates (very visible are Fuchengmen, Qianmen (still there) Chongwenmen, Andingmen etc), that really only exist today in the subway stop names (ie "Men") or street names (ex. Yongdingmen to the far south past Tiantan). The 1950s saw the first major modern change to the face of Beijing when the city walls were almost entirely torn down so that roads (namely the 2nd Ring Road) could be created. These changes went hand in hand with the rapid building that went on during this period. At that time, there were some city planners who opposed the idea of these changes, but they were shot down due to the need for "modernization."
From the late 1950s-early 1960s on, the building changes Beijing faced were relatively minor and the city remained relatively consistent from the 60s to the 70s to the early 80s (though it was slowly expanding out). However, by the mid to late 1980s, the city's face slowly started to change as the hutongs started being demolished again and bigger apartment blocks, malls, hotels, etc started to be built in their place. There was a brief pause in the late 80s, but things started picking up again in the early to mid 90s with rapid development in the late 90s in preparation for the 1999 50th anniversary of the founding of modern China. The most obvious changes were all around the center of the city mostly along (and under) Chang'an Avenue. The huge sparkling glass complex that is the Oriental Plaza stretching from Dongdan to Wangfujing opened up, the Line 1 subway was extened all the way to Sihuidong, and Wangfujing was closed off to cars and made a pedestrian street (China's first?).
The building and redevelopment didn't slow down, but lacked the kenetic pace of necessity after the ceremonies were done. However, July 13, 2001, would change all that as Beijing's successful Olympic bid would mean that changes would be on their way. As a comparison to the above, here's a more current image of Beijing (click on it):
So where is this all going? If you happened to be in Beijing in 1950 and left and then were dropped into Beijing circa 2006, you would think you were placed on another planet. The only thing that remained constant is basically the Forbidden City and the street names, though some of them only serve as depressing reminders (a la the Xidan of my childhood and today's Xidan, where the street names still have hutong in them (piku, picai, etc), though nothing else is the same). Why am I bringing this up? Hehe, for that you'll have to wait until a later date...Sorry for the history lesson, but it will all be worth it in the end, promise!