A "Double-Decker" typically refers to a type of bus that has two levels, allowing for more passengers compared to a single-decker bus. These buses are commonly found in cities like London, where they are an iconic part of public transportation. The upper deck often provides a better view of the surroundings, making it a popular choice for tourists. In addition to buses, the term "double-decker" can also describe a style of sandwich that has two layers of filling between three slices of bread. This type of sandwich is often stacked high and can include various ingredients, such as meats, cheeses, and vegetables, making it a hearty meal option.