The noodle soup originated in North Vietnam in the early 20th century, with Nam Định province southeast of Hanoi considered its birthplace. The broth simmers for hours from beef bones with roasted onion and ginger, seasoned with star anise, cinnamon, and cloves; Phở bò is served with beef, Phở gà with chicken. In the north, the broth is clear and savory; in the south, it's slightly sweeter, accompanied by a plate of fresh herbs and sprouts.