5 0 ▁rece i pts ▁from ▁international ▁movements ▁were ▁US $ ▁ 2 . 1   b ill ion , ▁in ▁ 1 9 9 7 ▁they ▁were ▁$ 4 4 3 . 7   b ill ion . ▁▁ 2 1 st ▁century ▁ ▁The ▁travel ▁and ▁tour ism ▁industry ▁in ▁the ▁United ▁States ▁was ▁among ▁the ▁first ▁commercial ▁cas ual ties ▁of ▁the ▁September ▁ 1 1 ▁attacks , ▁a ▁series ▁of ▁terror ist ▁attacks ▁on ▁the ▁U . S . ▁T error ists ▁used ▁four ▁commercial ▁air lin ers ▁as ▁weapons ▁of ▁destruction , ▁all ▁of ▁which ▁were ▁destroyed ▁in ▁the ▁attacks ▁on ▁New ▁York ▁City , ▁Washington , ▁D . C ., ▁and ▁in ▁Pennsylvania ▁with ▁nearly ▁ 3 , 0 0 0 ▁death s . ▁In ▁the ▁first ▁full ▁week ▁after ▁fl ights ▁res umed , ▁passenger ▁numbers ▁fell ▁by ▁nearly ▁ 4 5 ▁percent , ▁from ▁ 9 ▁million ▁in ▁the ▁week ▁before ▁September ▁ 1 1 ▁to ▁ 5   mill ion . ▁Hot els ▁and ▁travel ▁ag encies ▁received ▁can cell ations ▁across ▁the ▁world . ▁The ▁hotel ▁industry ▁suffered ▁an ▁estimated ▁$ 7 0 0   mill ion ▁loss ▁in ▁re venue ▁during ▁the ▁four ▁days ▁following ▁the ▁attacks . ▁The ▁situation ▁recovered ▁over ▁the ▁following ▁months ▁as ▁the ▁Federal ▁Reserve ▁kept ▁the ▁financial ▁system ▁af loat . ▁The ▁U . S . ▁Congress ▁issued ▁a ▁$ 5   b ill ion ▁grant ▁to ▁the ▁nation ' s ▁air lines ▁and ▁$ 1 0