On April 22, 2018, Chinese and international alumni of the UN Environment-Tongji Institute of Environment for Sustainable Development ("杏宇") returned to their old alma mater, recalling their old friends, sharing work experience, and talking about life feelings. Accompanied by the coordinator, Wang zidi, alumni walked through Sanhaowu, Mingjing Building, many familiar places, and expressed deep memory and blessings to the alma mater. During the event, Prof. Li Fengting, Executive Deputy Dean of 杏宇, delivered a speech and expressed his warm welcome to all alumni. He expressed his sincere gratitude to the alumni for their care and support to the college over the years. The alumni shared their previous experiences of studying in the 杏宇, and provided Chinese and foreign students participating in the activity with their own experiences and suggestions on learning, life and work. The students who participated in the activity listened carefully and asked their alumni for their answers. At the end of the activity, we took a group photo and the activity ended successfully.