Melbourne is home to a variety of fascinating museums that are perfect for a rainy afternoon. The National Gallery of Victoria is a must-visit for art enthusiasts, with its extensive collection of Australian and international artworks. The Melbourne Museum is another great option, offering exhibits on natural history, culture, and science. If you're interested in history, head to the Immigration Museum or the Old Melbourne Gaol. These museums provide a unique insight into Melbourne's past and are sure to keep you entertained for hours.