4840
Women 's football became popular on a large scale at the time of the First World War , when employment in heavy industry spurred the growth of the game , much as it had done for men fifty years earlier .
 event: First World War
Please list all entity words in the text that fit the category.Output format is "type1: word1; type2: word2". 
Option: media, plant, vehicle, astronomical object, time, disease, animal, location, person, organization, mythical figure, food, biology, geographical phenomenon, instrument, event 
Text: {0} 
Answer:
 event: First World War