Moscow

The original recipe was a restaurant secret and it died with its chef.

Lucien Olivier created the salad in the 1860s at the Hermitage, one of Moscow's grandest restaurants, and the first version used game, crayfish tails, and capers. He never published the method. The Soviet version swapped the luxuries for boiled potato, carrot, peas, and sausage, and outside Russia the same dish is usually called Russian salad.