Carlos Slim Helú was the richest man in the world from 2010 to 2013, and while he has fallen from No. 1, Slim is still worth $55.3B. From real estate to telecom, his business empire accounts for 40% of the listings on the Mexican Stock Exchange and his private wealth equals 6% of Mexico's gross domestic product. While Slim has numerous real estate investments, we decided to zoom in on four properties.

1. 1 Pepsi Way

A company linked to Slim's empire bought the old PepsiCo Americas Beverages' headquarters in Westchester County, N.Y., for almost $87M in March 2015. Slim bought the nine-story, 540k SF building to serve as an investment, according to his spokesperson. While it is not clear which tenants will fill the 200-acre campus, experts predict it will most likely morph into a mixed-use facility to serve sports, restaurant and possibly biotech tenants.

2. Benjamin N. Duke House

Slim bought this 20k SF NYC mansion, originally built in 1901, for $44M in 2010. It is one of the only surviving Beaux Arts mansions on Fifth Avenue and stands eight stories with a view of the Metropolitan Museum of Art. Slim put the property on the market for $80M in May 2015, but it failed to sell and was taken off in January 2016.

3. Detroit's Marquette Building

Through another limited liability company, Slim bought the Marquette Building in downtown Detroit for $5.7M in 2015. The sale marked his first purchase in Detroit, but followed Slim's business model of buying troubled assets at depressed prices to sell when markets rebound. The building was almost entirely empty when he purchased it. His strategy worked. Just a few months ago, he sold the 162k SF property to Adient for approximately $25M.

4. Mexico City home

Despite his billions, Slim has lived in the same Mexico City home for over 40 years. With six bedrooms and eight bathrooms, the home is in the city's exclusive Lomas de Chapultepec district and only a mile from Slim's office and three miles from where he was born.