May 18th is National Museum Day, so what better way to celebrate than highlighting the ones most visited in America?

划线部分应该是一个修辞性问句。

What is the better way to celebrate than highlighting the ones most visited in America?

修辞性问句不需要回答，实际表达的是肯定的意义：没有比点亮参观人数最多的几个博物馆更好的庆祝方式了---将访问人数最多的几个博物馆用彩灯装饰是最好的庆祝方式。