Why do they call it a "Waldorf salad"?

If you're among the many people who've wondered why they call it that, wonder no more...I found the answer:  

Waldorf salad [WAWL-dorf] Created at New York's Waldorf- Astoria Hotel in the 1896 not by a chef but by the maitre d'hotel Oscar Tschirky, the Waldorf salad was an instant success.the original version of this salad contained only apples, celery and mayonnaise. Chopped walnuts later became an integral part of the dish. Waldorf salad is usually served on top of a bed of lettuce.

Here's a recipe:

Waldorf Salad  

Ingredients:
1/4 cup Mayonnaise
1/4 cup plain yogurt
2 teaspoons Sugar
2 teaspoons Lemon juice
2 Apples
2 large Celery stalks
1/2 cup chopped walnuts  

Instructions In small salad bowl, combine mayonnaise, yogurt and lemon juice, to taste. Core apples, cut into bite size pieces, dice celery. Add both to salad bowl, fold in nuts. Chill up to two hours. Toss before serving.  

Variations: bananas, pecans, peaches, peanuts. You can also add 1 cup of shredded cooked chicken.  Just about anything can work to add a new flare or twist to your salad.