Who plays Trinity in 'The Matrix'?

In 'Raiders of the Lost Ark', what artifact are the characters searching for? What animal is Indiana Jones famously afraid of? Who played Indiana Jones's father in 'Indiana Jones and the Last Crusade'? In 'The Matrix', who plays Agent Smith? In 'Gladiator', what is the name of Russell Crowe's character? In 'Gladiator', who plays the emperor Commodus? In 'Braveheart', which Scottish hero does Mel Gibson play? In 'Titanic', what is the name of the necklace's giant blue diamond?