Local people of Hoi An are very religious. Every Full moon and New moon days (day before and the day) most of local people become vegetarian and Quan Chay (Vegetarian in Vietnamese) Restaurants are full of people you can't even find tables. There is Full Moon Festival on a night before full moon day in Hoi An Ancient Town, The town is filled with lanterns instead of street lights, no cars or motorbikes are allowed in town so you can walk around safely. It is held every full moon so if you plan to go to Hoi An, check lunar calendar to make sure you will be staying for full moon!!!