Tripoli's old medina is the centre of everything worth seeing. The walled quarter covers about a square kilometre and holds the city's mosques, souqs, and its most impressive monument — the Red Castle. Outside the medina, the waterfront corniche offers views across the harbour, and the Arch of Marcus Aurelius marks the site of the old Roman town.
Access to some sites depends on security conditions and local permissions, which shift. A local guide or licensed tour operator is strongly recommended.