After my morning flight home was canceled, I had two choices: I could panic, or I could chow down another croque monsieur and make the most of every minute in Paris. I chose the latter.

Thanks to a cheap airline, my friend and I were able to swing a couple tickets to Paris on a college budget. The downside to cheap flights is that they don’t always depart as scheduled. With nine hours to kill, we hopped on the metro toward Vincennes.

Over the course of our week-long trip, we hit all the top tourist attractions in Paris. But with the exception of Versailles, we hadn’t ventured out of the city. This was the perfect opportunity.

Vincennes, an eastern suburb of Paris, is about a 30-minute metro ride from the city’s center.

From the metro stop, a short walk down the Avenue de Paris brings you to the Chateau de Vincennes, a 12th-century medieval fortress. It’s billed as the tallest medieval donjon in Europe.

When I stepped off the metro, I arrived at the castle of my childhood dreams, complete with turrets, a moat, and a drawbridge. The only thing missing was the dragon. A friend studying in Paris had recommended we go to Vincennes — now I saw why.

Over the centuries, the Chateau de Vincennes has served various functions, from royal residence to fortress to prison to museum. It dates back to around 1150, when Louis VII constructed his hunting lodge on the site.

Charles V completed construction of the keep, which is over 170 feet tall. An enclosure wall was built between 1372 and 1380 to protect the village around the keep. The wall is more than 3,600 feet long, with nine towers.

Once I crossed the drawbridge, it felt as though I stepped back in time. Cobblestone paths lead to the center of the village, with the ornate Sainte-Chapelle to the left and the keep to the right. It was hard to decide which of these towering landmarks to visit first.

We went with the keep. A moat runs along the perimeter, with grass growing where water once flowed. The moat wall is decorated with a flame-like pattern.

Even though our legs were still sore from climbing the Eiffel Tower, we managed to make it up the turret’s winding steps to the parapet. There, we walked along the castle’s defensive wall. It was strange to watch cars buzz by, just outside the walls of the medieval enclosure.

Unlike the Louvre or the Arc de Triomphe, the Chateau de Vincennes wasn’t mobbed. We didn’t have to elbow our way through crowds of people; we were free to roam the castle at our leisure. It was a much more intimate experience than struggling to see past the outstretched arms of tourists snapping selfies with the Mona Lisa.

Inside the keep, we wandered through the second floor, which was once the king’s bedchamber. Here, Charles V once stored gold, silver, and manuscripts from his library.

Now, there isn’t much left in the keep. We navigated through stone corridors to rooms that were mostly vacant, aside from plaques that detail the chateau’s history. On the lower level, they tell the story of the keep’s prisoners.

Louis XI began holding prisoners in Vincennes in the late 15th century. Many of Vincennes’s prisoners over time were political and religious dissenters. By the 17th century, the keep became a place for solitary confinement. The keep was used as a prison until the 19th century.

After strolling through the castle, my friend and I made our way to the Sainte-Chapelle. It’s just as beautiful as the chapel it was modeled after — the Sainte-Chapelle on the Ile de la Cite in Paris.

Charles V began work on the Sainte-Chapelle in 1379. Construction was finished in 1552 by Henri II. It’s believed that part of the cross and a piece of the crown of thorns were once held here.

Inside, the Sainte-Chapelle at Vincennes has a bright, airy feel. Even in a rainstorm, hints of sunlight streaked through the pastel-colored stained glass. Two large, circular windows occupy either end of the long chapel.

Our legs have never been so sore, but we took a “when in Paris’’ approach, and climbed yet another spiral staircase to the chapel’s balcony. Here, we got a closer look at the ribbed vaulted ceilings and the stained glass. I could have stayed all day, marveling at the architectural detail.

The Chateau de Vincennes was well worth the short trip out of Paris. A word of advice: Don’t wait until your flight gets canceled to check it out.

Tickets are required to enter the keep and Sainte-Chapelle. General admission is 9 euros. The Chateau de Vincennes can be reached via Metro Line 1.

Nicole DeFuedis can be reached at Nicole.DeFeudis@globe.com.