The Earth Simulator, developed by the Japanese government's initiative Earth Simulator Project, is a highly parallel vector supercomputer system that consists of 640 processor nodes and interconnection network. The processor node is a shared memory parallel vector supercomputer, in which 8 vector processors that can deliver 8GFLOPS are tightly connected to a shared memory with a peak performance of 64GFLOPS. The interconnection network is a huge non-blocking crossbar switch linking 640 processor nodes and supports for global addressing and synchronization. The aggregate peak vector performance of the Earth Simulator is 40TFLOPS, and the intercommunication bandwidth between every two processor nodes is 12.3GB/s in each direction. The aggregate switching capacity of the interconnection network is 7.87TB/s. To realize a high-performance and high-efficiency computer system, three architectural features are applied in the Earth Simulator; vector processor, shared-memory and high-bandwidth non-blocking interconnection crossbar network. The Earth Simulator achieved 35.86TFLOPS, or 87.5% of peak performance of the system, in LINPACK benchmark, and has been proven as the most powerful supercomputer in the world. It also achieved 26.58TFLOPS, or 64.9% of peak performance of the system, for a global atmospheric circulation model with the spectral method. This record-breaking sustained performance makes this innovative system a very effective scientific tool for providing solutions to the sustainable development of humankind and its symbiosis with the planet earth.