Major hotels in San Antonio are concentrated in three areas: downtown along the River Walk and near the Alamo; north near the airport and North Star Mall; and northwest along the Interstate 10 corridor, near the South Texas Medical Center Complex and Six Flags Fiesta Texas. The city's packed calendar of festivals and conventions attracts many visitors. Therefore, make your reservations well in advance, especially for Holy Week (when many Mexican nationals make an annual pilgrimage to San Antonio to shop), during December's holiday festivities on the River Walk and during April's 10-day Fiesta San Antonio. Six Flags Fiesta Texas and SeaWorld draw many summertime guests to hotels and motels north and northwest of downtown, especially on weekends.