Taipei, the bustling city of today, used to have a wall with 5 gates something over a century ago. What remains today are 4 gates, of which only 1 survived in its original form. All gates were constructed between 1879 and 1884 during the rule of the Qing Dynasty. One gate (namely the West Gate) and the wall were destroyed and removed by the Japanese during their occupation of Taiwan (1895-1945) and was never reconstructed. The CKS government of the Republic of China (Taiwan) modified 3 of the 4 remaining gates in 1966 by changing the upper part of the original gates into a northern Chinese style architecture (supposedly "to make Taipei more attractive to tourists", that worked out well, didn't it?) and that's why there's only one gate in its original form today (namely the North Gate).
1 List of the historic gates of Taipei
Please click on the photos to read an article about a particular gate.
2 Location map of the historic gates of Taipei
Here you can see where the gates stand today. The West Gate doesn't exist anymore.
3 Timeline of rulers over Taiwan (links to Wikipedia)
Before WWII: [Qing Dynasty 1683-1895][Japanese occupation 1895-1945]
After WWII: [Kuomintang 1945-2000][DPP 2000-2008][Kuomintang 2008-]
4 Related posts and more info (in traditional Chinese)
[Gates of Taipei Wikipedia][Gates overview: 城門的建築型式][Blog post with maps]
[Blog post about history of Taipei's walls and gates][NCYU article about the gates]