Group 1 - The article discusses the significance of the solar term "Great Heat," which is the twelfth of the 24 solar terms and marks the peak of summer heat in China, starting on July 22, 2025 [2] - It highlights the historical context of summer clothing, emphasizing the use of lightweight and breathable fabrics such as silk and hemp, which were essential for comfort during hot weather in ancient China [2] - The article mentions the evolution of summer clothing from the Han dynasty to the Song dynasty, showcasing advancements in textile techniques and the continued popularity of natural fibers [2] Group 2 - The article describes ancient cooling methods, including the creation of ice-based desserts like "Su Shan," which dates back to the Tang dynasty, and the popularity of cold drinks in the Song dynasty [3] - It explains the historical methods of ice collection and storage, noting that ice was a precious commodity in ancient times, often sourced from rivers in winter and stored for summer use [3] - The article also details the emergence of ice merchants during the Tang dynasty, who sold ice to the public, indicating a growing demand for cooling products [3] Group 3 - The article outlines architectural designs in ancient homes aimed at cooling, such as the orientation of buildings to maximize airflow and the use of courtyards and water features to lower indoor temperatures [4] - It mentions the luxurious cooling spaces like "Cool Palaces" that were reserved for the elite, while common households relied on various cooling tools like fans and bamboo mats [5] - The article concludes with a reference to leisure activities in nature as a means of escaping the summer heat, highlighting the cultural practices of ancient people [5]

Core Points - The main event of the Cultural and Natural Heritage Day is being held in Changsha, which is described as a "museum without walls" [1][4] - Changsha is recognized as one of the first national historical and cultural cities in China, with a history dating back 150,000 to 200,000 years [4][5] - The city features numerous museums and cultural sites, showcasing a rich collection of historical artifacts and treasures [10][11] Summary by Categories Cultural Significance - Changsha is referred to as a "museum without walls," highlighting its extensive cultural heritage and historical significance [4][10] - The city has witnessed significant historical events from various dynasties, including the Qin, Han, Tang, and Song [4][5] Museums and Exhibitions - There are 32 state-owned museums and 20 private museums in Changsha, collectively housing numerous national treasures [10] - The article lists several must-see national treasures, including the "Su Sha Dan Yi" and the "T-shaped Silk Painting," which reflect ancient wisdom and cultural beliefs [11][13] Upcoming Exhibitions - Multiple special exhibitions are organized during the Cultural and Natural Heritage Day, including "Endless Yangtze River - The Yangtze and Chinese Civilization Exhibition" and "Searching for Ancient States in the Records of History" [39][41] - These exhibitions are free to the public and feature significant artifacts from various ancient cultures, enhancing the cultural experience for visitors [39][41][44]