There are many successful real estate investors who have amassed significant wealth through their investments. It's difficult to determine the exact ranking of the richest real estate investors, as this can vary based on a variety of factors, such as the value of their portfolio, the market conditions, and the investor's level of success.

Some well-known real estate investors who have achieved significant wealth through their investments include:

Sam Zell: Sam Zell is a real estate investor and chairman of Equity Group Investments, a private investment firm. He is known for his successful investments in a variety of real estate assets, including apartments, hotels, and office buildings.

Donald Trump: Donald Trump is a real estate developer and former president of the United States. He is known for his successful investments in a variety of real estate assets, including office buildings, hotels, and residential properties.

Howard Hughes: Howard Hughes was an American business magnate, investor, and philanthropist who made significant investments in real estate. He is known for his successful investments in a variety of real estate assets, including office buildings, hotels, and residential properties.

Warren Buffett: Warren Buffett is an American business magnate and investor who is known for his successful investments in a variety of industries, including real estate. He is the CEO of Berkshire Hathaway, a multinational conglomerate that owns a number of real estate assets.

Sam Warburg: Sam Warburg is a real estate investor and founder of the real estate investment firm Blackstone Group. He is known for his successful investments in a variety of real estate assets, including apartments, hotels, and office buildings.