The famous El Floridita (corner of Monserrate and Calle Obispo, tel. 07/867-9299, 11:30 a.m.–midnight) restaurant and bar has been serving food since 1819, when it was called Pina de Plata. It is haunted by Ernest Hemingway’s ghost. You expect a spotlight to come on and Desi Arnaz to appear conducting a dance band, and Hemingway to stroll in as he would every morning when he lived in Havana  and drank with Honest Lil, the Worst Politician, and other real-life characters from his novels.
Hemingway’s bronze bust watches over from its pedestal above the dark mahogany bar where Constante Ribailagua once served frozen daiquiris to the great writer (Hemingway immortalized both the drink and the venue in his novel Islands in the Stream) and such illustrious guests as Gary Cooper, Tennessee Williams, Marlene Dietrich, and Jean-Paul Sartre. There’s even a life-size bronze statue of Hemingway, by sculptor José Villa, leaning with an elbow upon the bar.
El Floridita has been spruced up for tourist consumption with a 1930s art deco polish. They’ve overpriced the place for the package-tourist crowd, but sipping a (watery) daiquiri at El Floridita is still a must.