New York City is back, baby. At least when it comes to the city's share of billionaires.

For years, Moscow and its ruble-hoarding oligarchs and businessmen have dominated the Forbes world ranking of cities with the highest number of billionaires. But a recent study by WealthInsight puts New York City back on top with 70 billionaire residents, while Moscow is relegated to No. 2, with a paltry 64.

London, Hong Kong and Beijing round out the top 5, followed by Mumbai and Istanbul.

Check out this interactive bubble map of the 20 cities with the highest billionaire populations in the world. A large bubble indicates a higher population of billionaires.