The Where Who Why (WWW) dataset provides 10,000 videos with over 8 million frames from 8,257 diverse scenes, therefore offering a superior comprehensive dataset for the area of crowd understanding. The abundant sources of these videos also enrich the diversity and completeness. The dataset can be download from either Baidu disk or Dropbox. Readme provides the details of the WWW Crowd dataset used in our paper which are archived here, including the crowd attributes list, movie list, training/test/validation sets, and the scene labels. The groundtruth annotations for all the videos in the WWW dataset can be downloaded here. We extract the first representative frame from each video in the dataset to build a single frame set. These data can only be used for academic research purposes.