In which movie does the villain "Darth Vader" first appear?

Star Wars: Episode IV – A New Hope

Which animal is known for detecting prey buried underground using incredible hearing? Which animal is known for its black and white coloring and smell defense? Sucre is one of the capitals of Bolivia; what is the other one? What Hungarian Christmas sweet treat is a rolled pastry filled with walnuts or poppy seeds? Who is the lead singer of the British metal band Iron Maiden?