A team of researchers from China has demonstrated satellite-based entanglement distribution over 1203 km between two ground stations. Using a satellite-to-ground two-downlink system, they achieved entanglement distribution between Delingha and Lijiang, and between Delingha and Nanshan, with an average two-photon count rate of 1.1 Hz and a state fidelity of 0.869 ± 0.085. The experiment observed a survival of two-photon entanglement and a violation of Bell inequality by 2.37 ± 0.09 under strict Einstein locality conditions. The effective link efficiency at 1200 km was over 12 orders of magnitude higher than direct bidirectional transmission through commercial telecommunication fibers. Quantum entanglement, first recognized by Einstein, Podolsky, and Rosen, and by Schrödinger, describes a physical phenomenon where the quantum states of a many-particle system cannot be factorized into a product of single-particle wave-functions, even when the particles are separated by large distances. Entangled states have been produced in laboratories and used to test the contradiction between classical local hidden variable theory and quantum mechanics using Bell's inequality. Entanglement distribution over long distances is essential for foundational tests of quantum physics and scalable quantum networks. However, previous achievements were limited to about 100 km due to photon loss in the channel. To overcome this, the researchers used a satellite to distribute entangled photons over 1203 km, achieving a significant improvement in link efficiency. The satellite, named Micius, was launched to an altitude of ~500 km and equipped with two telescopes to establish two independent satellite-to-ground quantum links. The experiment involved developing ultrabright spaceborne two-photon entanglement sources and high-precision acquiring, pointing, and tracking (APT) technology. The entangled photons were distributed through a satellite-to-ground two-downlink system, with the effective channel length varying from 1600 km to 2400 km. The experiment used a CHSH-type Bell inequality test to verify the non-local feature of entanglement and exclude models of reality based on locality and realism. The observed violation of the Bell inequality by 4 standard deviations confirmed the non-local nature of entanglement at a scale of thousands of kilometers. The results demonstrate the feasibility of satellite-based entanglement distribution over long distances and open up new avenues for practical quantum communications and fundamental quantum optics experiments at distances previously inaccessible on the ground. The developed satellite-based technology is also useful for entanglement-based quantum key distribution and remote preparation and control of quantum states.A team of researchers from China has demonstrated satellite-based entanglement distribution over 1203 km between two ground stations. Using a satellite-to-ground two-downlink system, they achieved entanglement distribution between Delingha and Lijiang, and between Delingha and Nanshan, with an average two-photon count rate of 1.1 Hz and a state fidelity of 0.869 ± 0.085. The experiment observed a survival of two-photon entanglement and a violation of Bell inequality by 2.37 ± 0.09 under strict Einstein locality conditions. The effective link efficiency at 1200 km was over 12 orders of magnitude higher than direct bidirectional transmission through commercial telecommunication fibers. Quantum entanglement, first recognized by Einstein, Podolsky, and Rosen, and by Schrödinger, describes a physical phenomenon where the quantum states of a many-particle system cannot be factorized into a product of single-particle wave-functions, even when the particles are separated by large distances. Entangled states have been produced in laboratories and used to test the contradiction between classical local hidden variable theory and quantum mechanics using Bell's inequality. Entanglement distribution over long distances is essential for foundational tests of quantum physics and scalable quantum networks. However, previous achievements were limited to about 100 km due to photon loss in the channel. To overcome this, the researchers used a satellite to distribute entangled photons over 1203 km, achieving a significant improvement in link efficiency. The satellite, named Micius, was launched to an altitude of ~500 km and equipped with two telescopes to establish two independent satellite-to-ground quantum links. The experiment involved developing ultrabright spaceborne two-photon entanglement sources and high-precision acquiring, pointing, and tracking (APT) technology. The entangled photons were distributed through a satellite-to-ground two-downlink system, with the effective channel length varying from 1600 km to 2400 km. The experiment used a CHSH-type Bell inequality test to verify the non-local feature of entanglement and exclude models of reality based on locality and realism. The observed violation of the Bell inequality by 4 standard deviations confirmed the non-local nature of entanglement at a scale of thousands of kilometers. The results demonstrate the feasibility of satellite-based entanglement distribution over long distances and open up new avenues for practical quantum communications and fundamental quantum optics experiments at distances previously inaccessible on the ground. The developed satellite-based technology is also useful for entanglement-based quantum key distribution and remote preparation and control of quantum states.