Marco, in turn, was amazed by how beautiful and powerful China was. He was very impressed by Beijing and the Emperor's Palace, especially the Summer Palace which he described as "The greatest palace that ever was...The walls were covered in gold and silver and the Hall was so large it could easily seat 6,000 people for dinner." There were invertions and developments in China which were not available in Europe at that time. Marco was surprised to see Chinese people using paper money in the markets. In Europe, people paid for goods with gold or silver. He could not understand how people could pay for food and valuable things with paper! He was also confused by the black stones people used to burn for fuel. The black stones were coal, but Marco had never see coal before!