The fortification Fortaleza San Felipe, which was built in the 16th century and served as a prison under Rafael Trujillo's dictatorship, lies close to the port of Puerta Plata. The amber museum, is also a well-known attraction in this city. La Isabela, a settlement built by Christopher Columbus, is located near Puerto Plata. In April 1563, the Spanish settlement became notorious when the English slave trader Sir John Hawkins brought 400 people he had abducted from Sierra Leone. Hawkins traded his victims with the Spanish for pearls, hides, sugar and some gold. This was the start of British involvement in the trans-Atlantic slave trade.