The historical city of Bam, Iran, was suddenly collapsed by an earthquake in December 2003. Shocked by the extensive damage of Bam, we immediately launched a project for reconstructing the collapsed city, which is now inscribed as UNESCO World Heritage in Danger. We started from data collection such as photographs before the earthquake, interpretation and integration of heterogeneous sources of data, and the 3D modeling of architecture using CAD and CG software. The goal of our project is to make an accurate 3D model that satisfies requirement from architects so that our model can be directly used for physical reconstruction in the future. The talk will introduce our nearly eight years of effort about how to make an accurate 3D model under poor documentation, and the combination of manual / automatic methods toward a cost-effective modeling process.