You will be given a trivia clue, and the category it belongs to. You should answer with the best answer that belongs in the category and is described by the clue. For simplicity, answers should be in all lower cased letters.

Category: TO THE "LEFT" HAND SIDE 
Clue: Artsy southern section of Paris
the left bank

Category: HALOGENS 
Clue: A reddish liquid, this halogen is often used to make sedatives & was once used to make EDB, an additive in lead gasoline
bromine

Category: TOURIST TRAPS 
Clue: Both Ferde Grofe' & the Colorado River dug this national park

the grand canyon