National Museum of the Middle Ages. The Hôtel de Cluny has been a museum since medievalist Alexandre Du Sommerard established his collection here in 1844. The over-the-top mansion was a choice location for such a collection; the 15th-century building was created for the abbot of Cluny, leader of the most powerful monastery in France. Symbols of the abbot's power literally surround the building, from the crenellated walls that proclaimed his independence from the king to the carved Burgundian grapes twining up the entrance to the scallop-shell decorations covering the facade. Coquilles-Saint-Jacques (scallops) symbolize pilgrimage and the great pilgrimage route to Spain, rue St-Jacques, once lay just around the corner. Now the hôtel holds a stunning array of tapestries, including the world-famous Dame à la Licorne (Lady and the Unicorn) series, woven in the 15th or 16th century, probably in Belgium. These tapestries represent the senses with allegorical tableaux; in each, a unicorn and a lion surround an elegant lady against an elaborate millefleur background. There are also stellar examples of Byzantine crosses, architectural fragments and medieval paintings. The collection includes the original sculpted heads of the Kings of Israel and Judah from Notre-Dame, discovered in 1977; these had been decapitated from the cathedral during the Revolution and hidden by a nobleman near today's Galeries Lafayette. At the Cluny you can also visit the remnants of the city's Roman baths -- both hot (caldarium) and cold (frigidarium), the latter containing the Boatmen's Pillar, Paris's oldest sculpture. The park includes a medieval garden filled with flora depicted in the unicorn tapestries. COST: EUR5.50, free 1st Sun. of month, otherwise EUR4 on Sun. Métro: Cluny La Sorbonne.