Built in 1660 by Louis XIV, Fort Saint-Jean is a well-preserved fortress guarding Marseille at the entrance to the Old Port. Interestingly, it was built not to keep invaders at bay but to tamp down a local rebellion. Later, in the 19th and 20th centuries, it was used by the French military until German military forces occupied it during WWII. Today, the storied fort is a tourist attraction, where travelers stretch their legs and relax rather than prepare for battle. 

Travelers of all ages rave about the peaceful atmosphere of Fort Saint-Jean and the wonderful views from the top. They also note that it's surprisingly accessible, with ramps and elevators. 

Visitors will need to enter through the attached MuCEM (and pay the 9.50 euro – about $11.60 – admission price to the museum) to reach Fort Saint-Jean. From May 2 to July 7 and Sept. 4 to Nov. 5, it's open from 11 a.m. to 7 p.m. From Nov. 6 to April 30, it's open from 11 a.m. to 6 p.m. and from July 8 to Sept. 3, it's open from 10 a.m. to 8 p.m. You'll find both attractions in Le Panier. For more information, visit Marseille Tourism's website.