What does whose broad strips and bright stars through the perilous?

The phrase "whose broad stripes and bright stars through the perilous fight" refers to the American flag, particularly its design and the symbolism it embodies. It evokes imagery of the flag waving during a challenging battle, representing resilience and hope. The "broad stripes" symbolize the unity of the states, while the "bright stars" represent the individual states themselves. This line is part of "The Star-Spangled Banner," which captures the spirit of perseverance amidst adversity.