A wide scarf crossed in front and secured with a stickpin. It's a very formal look that you don't see much these days.
This is the classic formalwear neckwear. The bow tie coordinates with a cummerbund or waistcoat. While a pre-tied bow tie was OK for the prom, the hand-tied version is more appropriate for the big day.
This is the familiar tie that's worn with a suit, in a dressier fabric. These days, a black four-in-hand tie is a popular option, but ties come in many colors and patterns.