Moderator note: Cairo, in this context, is pronounced "CAY-row", not "KYE-row".
Moderator note: Cairo, in this context, is pronounced "CAY-row", not "KYE-row". Asian carp comprise more than 95% of fish biomass in some areas of this river, which was invaded by carp in the early 90s. A bridge crossing this river's St. Anthony Falls collapsed in 2007, killing 13 people. An elephant was led across the Eads Bridge over this river in 1874. Two hundred thousand people were forced to relocate after its devastating 1927 floods. The (*) New Madrid seismic zone is on this river. Its lower and upper branches meet at Cairo. This river flows through Natchez and Vicksburg before meeting Lake Ponchartrain on its southern course. For 10 points, name this river which flows into the Gulf of Mexico, the longest in the US.
Moderator note: Cairo, in this context, is pronounced "CAY-row", not "KYE-row".
Mississippi River [prompt on Illinois River]