May 2000 is the earliest the Google Earth allows us to go. Much of the northwest quarter of the old town 上海老城厢 used to be known as Jiumudi 九亩地. We can see that the northern edges of the old town have been modernized prior to 2000, and there is a gaping hole waiting to be built up.
November 2000: the final removal of a small residential block at the intersection of Fangbang Lu 方浜中路 and Henan Nan Lu 河南南路 allows to complete the construction of the northern block of Taiyang Dushi Huayuan 太阳都市花园 and Jiari Apartments 佳日公寓. There is also a small rectangular empty lot along Henan Nan Lu. This is where Yunju Nunnery 云居庵 stood since 1644 until it was demolished in 1997. The reason? The widening of the road.
2002: A strip of narrow residential blocks along the western edge of the old town is replaced with a "green belt". Further north, a lot is being cleared out at the crossing with Dajing Lu 大境路. At the upper right corner, a residential block is removed and replaced by the lawn. But this is not the end of the transformations.
2004: A little miracle: 'old' Taoist temple Baiyunguan 白云观 suddenly appears on the cleared lot next to the Dajing Pavilion 大境阁. The temple is marked as 'protected historic architecture' although not only it was built anew at the new spot, it was also "moved" from its original location at Fangxie Lu 方斜路, which means it was demolished there first.
Also, note the disappearance of the trees along Henan Nan Lu and the shrinking of the lawn at the top right corner.
2008: The outlined area might look normal, but if you compare it with the previous shot, the holes are starting to show in the tapestry of the roofs: the houses are beginning to disappear. Jiumudi historic blocks are dissolving.
May 2009: Wow. Gone. Except for a few lingering houses on the street corners, everything is wiped out.
October 2009: Perhaps, the only bright moment in the whole process. The demolished area gets spontaneously reforested. By 2010, young trees are reaching the height of the few surviving buildings.
2010: The latest snapshot from Google Earth.
2011: a plan introducing upscale redevelopment and mixed-use zone was spotted on the walls. Some houses were marked as 'stayers-on'. The plan was taken down soon. Some of the selected houses – demolished.
This is how much was demolished in ten years. Was Jiumudi a slum? Were the buildings worth keeping? Thanks to the detailed survey and maps created by the Tongji University team, we can tell that the area consisted primarily of lane compounds dating back to 1911-1912 (more and more rare in Shanghai), and some standalone mansions of finer styles, formerly private residences. The 2006 survey marked 56 buildings of 'historic value' inside the wiped out area (this rank was only assigned to the buildings facing the road – that constituted the streetscape, basically). The interiors of the blocks received lower rank, although they frequently belonged to the same compounds and shared the same pedigree.