On this day, 49 years ago, July 28, 1976 (July 2, 1976, the Tangshan earthquake killed 240,000 people. The epicenter intensity was 11 degrees, the bridge collapsed, and traffic was completely interrupted. At 3:42: 53.8 seconds on July 28, 1976, an earthquake measuring 7.8 on the Richter scale occurred in Tangshan and Fengnan areas in Hebei Province, China (118.2° east longitude, 39.6° north latitude)(moment magnitude 7.5), with an epicenter intensity of 11 degrees, a focal depth of 12 kilometers, and the earthquake lasted for about 12 seconds. The earthquake killed 242769 people and seriously injured 164,000 people, ranking second in the world's earthquake history in the 20th century, second only to the Haiyuan earthquake. On July 28, 1976, the 23 seconds after 3:42: 53.8 seconds Beijing time were definitely an unforgettable 23 seconds for China people of that era; For the Tangshan people who personally experienced those 23 seconds and survived, these 23 seconds are deeply engraved in their memories of the pain and unspeakable terror-July 28, 1976, at 3 a.m., 42 minutes, 53.8 seconds, Tangshan, a major earthquake! Within 23 seconds, a major earthquake measuring 7.8 on the Richter scale occurred in Tangshan, located in North China; within 23 seconds, more than 242,000 people were killed and more than 164,000 people were seriously injured; within 23 seconds, more than 7200 families died in the earthquake, tens of thousands of families disintegrated, and 4204 people became orphans; Within 23 seconds, 97% of the ground buildings and 55% of the production equipment were destroyed; within 23 seconds, transportation, water supply, power supply, and communications were all interrupted; within 23 seconds, direct economic losses were RMB 3 billion; within 23 seconds, an industrial city with a population of one million was razed to the ground. Tangshan, the emerging heavy industrial city, suffered a severe disaster and was reduced to ruins. The epicenter of the earthquake was located in the Jixiang Road area in Lunan District of Tangshan, that is, 39 degrees 38 'north latitude and 118 degrees 11' east longitude. The epicenter intensity reached 11 degrees and the focal depth was 12 kilometers. The extreme earthquake zone extends in all directions with Tangshan as the center, about 47 square kilometers. Most of the old areas of Tangshan City are old-fashioned single-story houses, which turned into rubble after the earthquake; most of the new areas in the Xinshi District are brick-concrete multi-storey buildings that almost collapsed; High-rise buildings with reinforced concrete frame structures have not been spared. Railway tracks have been snake-shaped distorted or undulating due to the sinking of the roadbed. Wide cracks have occurred on the ground. Bridges have generally collapsed. Seismic structural cracks have extended for up to 8 kilometers. Ground movements near the crack zone are so astonishing that even people are thrown into the air within two of more than 200 meters. The impact area of the earthquake is extremely large. The strong earthquake affects a vast area in eastern China. It starts from Manzhouli in Heilongjiang in the north, reaches Piaohe in Henan in the south, borders Bohai Bay in the east, and reaches Mingzui Mountain in Ningxia in the west. Hundreds of millions of people living on more than 2 million square kilometers of land were disturbed. The area damaged by the earthquake is about 210,000 square kilometers, including more than 30,000 square kilometers of severely damaged areas. A large number of houses in the area collapsed, farmland was silted up with sand, canals and water were blocked, and roads, railways and bridges were damaged. According to the total number of people in the Beijing-Tianjin-Tangshan region, more than 242,000 people were killed in the earthquake, more than 164,000 people were seriously injured, and countless people were slightly injured. Mao Zedong was extremely concerned about the disaster relief situation in Tangshan. During his serious illness, he reviewed relevant reports many times. A central condolence group headed by Premier Hua Guofeng sent by the Central Committee of the Communist Party of China and the State Council arrived in the disaster area to cordially visit the affected people. During this period, the China government announced to the public that the China people are determined to overcome difficulties in a spirit of self-reliance and refuse external assistance. After a large number of disaster relief personnel arrived in Tangshan, disaster relief work in Tangshan was in full swing. On August 4, a central condolence group headed by Hua Guofeng went to the disaster area to express condolences to the people. The central government established an earthquake relief headquarters. More than 100,000 People's Liberation Army and more than 20,000 medical personnel and tens of thousands of support personnel from various parties rushed to the disaster area. After more than 20 days of emergency rescue work, the disaster was initially brought under control. Due to the implementation of a series of epidemic prevention and control measures, there was no epidemic of plague in Tangshan City after the earthquake. After the earthquake, the People's Liberation Army Air Force of Tangshan City dropped earthquake relief supplies to the disaster area. After the Tangshan earthquake, China's North China area entered a state of earthquake prevention. The picture shows the "earthquake-proof shed" built on the streets of Beijing. People in the temporary earthquake shed, children from Tangshan Orphanage, Shengli Bridge, Tangshan City, rescue soldiers rushed to the disaster area