August in Madrid usually means a citywide exodus. As families vacation along Spain's famous coastlines, the traffic eases and the capital becomes a bit less congested. Next August promises to be very different. Members of the Organizing Committee of the World Youth Day 2011 expect that up to 2.5 million Catholics will descend on the city for the Aug. 16-21 international event. To accommodate this influx, the committee will secure space in Madrid's three dioceses at locations such as universities, recreation centers and school gymnasiums. Many pilgrims will sleep on the mats or in sleeping bags. Soon the Vatican will release a list of more than 2,000 bishops who will conduct informal catechesis every morning followed by a number of cultural events in the evenings. Young Catholics can look forward to concerts, plays, and some of the best museums and palaces in the world. By mid-September, 144,000 groups from outside Spain had registered for World Youth Day, with two-thirds of them scheduled to attend Days in the Dioceses, which allows them to spend time in other parts of Spain before World Youth Day begins Aug. 16. Sixty of Spain's dioceses will participate in the Days in the Dioceses.