Cologne Cathedral is the representative work of Gothic architecture art in medieval Europe. It is the most perfect Gothic church building and the highest twin-tower Church in the world. Built in 1248, it took 600 years to complete. It is known as the three major religious buildings in Europe together with Notre Dame Cathedral in Paris and St. Peter Cathedral in Rome. Cologne Cathedral is also the largest church in Germany, the only historical building that Cologne retained during World War II. It is the landmark of Cologne and is listed as an endangered world cultural heritage by UNESCO World Heritage Committee. Cologne Cathedral shocked every visitor with its magnificent appearance, magnificent dome, exquisite relief, dazzling painted glass windows, and the famous treasure of the town hall - the golden carved box containing the coffins of the three sages who welcomed the birth of Jesus. Its artistic value is unparalleled. It is also a religious museum with many precious collections and paintings from the Bible. As soon as I entered the church, I was shocked by the magnificence of the central chapel. The dome of the lobby is 43 meters high and the span of the hall is 15.5 meters. It is the highest hall in the world. There are 5700 neat wooden seats in each hall and 104 seats for clergy, all made of very thick wooden boards. The whole church was solemn and solemn, which prompted a sense of awe. The four walls of the church have a total area of more than 10,000 meters and are fully equipped with stained glass depicting biblical figures. It is called the French Flame. Painting only uses four colors: yellow implies light and eternity; red represents love; blue represents faith; green represents hope and future. Reflected by the sun, these glasses glisten with gold and colour. Moreover, the firing process of these glasses is very exquisite and the materials are expensive. Red glass is made of gold, blue glass is made of silver, and yellow glass is made of copper. The glass windows of Cologne Cathedral are a beautiful feature of it.