Miami Beach South Beach Real Estate and Condos by Mark Zilbert - Miami''s Million Dollar Realtor. Zilbert.com is an leading online real estate website for Miami Real Estate, featuring waterfront luxury condos and homes. Zilbert.com is a brand of luxury real estate based in Miami, founded by Mark Zilbert and Zilbert (formerly Zilbert International Realty, Zilbert Realty Group). Mark Zilbert is a Miami Beach expert and Realtor. Mark specializes in luxury, waterfront condos and homes in Miami Beach and South Beach in Florida. Miami Beach preconstruction condos are also a speciality of Mark, as well as South Beach condos.