A contract has been signed for what will be the most expensive apartment sale in New York City history, according to today’s Times. A “London-based businessman in the oil business” — for shame, local hedgies! — will pay $56 million for a triplex penthouse in the converted-to-condos Plaza Hotel. It occurs to us: With that same $56 million, by way of comparison, you could lease 100 Manhattan one-bedrooms — Citi Habitats puts the current average monthly one-bedroom rent at $2,567 — for a bit more than eighteen years. That’s all.