Task: Question Generation
Input (English): Because of the city's prominent role in the American Revolution, several historic sites relating to that period are preserved as part of the Boston National Historical Park. Many are found along the Freedom Trail, which is marked by a red line of bricks embedded in the ground. The city is also home to several art museums, including the Museum of Fine Arts and the Isabella Stewart Gardner Museum. The Institute of Contemporary Art is housed in a contemporary building designed by Diller Scofidio + Renfro in the Seaport District. The University of Massachusetts Boston campus on Columbia Point houses the John F. Kennedy Library. The Boston Athenaeum (one of the oldest independent libraries in the United States), Boston Children's Museum, Bull & Finch Pub (whose building is known from the television show Cheers), Museum of Science, and the New England Aquarium are within the city.
Output (English): What is marked by a line of red bricks in the ground?