The Havana Seawall FKT is a 8.36 mile out-and-back along the Malecón, Cuba’s iconic coastal esplanade. The course begins and ends at the official marker at the mouth of Havana Harbor in Old Havana (adjacent to Castillo de Salvador, the restored 16th century fortress) and continues west past the Centra Habana and Vedado neighborhoods, reaching the turnaround at the mouth of the Almendares River.
Havana’s iconic esplanade was constructed beginning in 1901 to protect Cuba’s capital city from the sea. For generations, The Malecón has served as a chief gathering place, parade grounds, fishing hole, and even the venue for the 1957 and 1958 Cuban Grand Prix.
You can read more of the history on Wikipedia: https://en.wikipedia.org/wiki/Malec%C3%B3n,_Havana