You have the unique opportunity to watch one of nature's most powerful, beautiful processes as the earth unfurls to release its magma from the volcanoes. As one of the most active volcanoes on the planet, Kīlauea volcano is consistently one of Big Island's biggest attractions. Its reputation precedes it as a sacred place for Native Hawaiians as well. Marvel at the active Mauna Loa, learn about volcanology at the Jaggar Museum, take a selfie at the viewpoint overlooking the Halema'uma'u Crater. The long, underground cave formed by ancient flowing lava called the Thurston Lava Tube (Nāhuku) is another must-see.

The Palacio Real de Madrid, the official residence of the Spanish royal family in the city, is Europe's largest royal palace, boasting a whopping surface area of 135,000 square metres and a staggering 3,418 rooms. This architectural marvel is not only visually stunning, but also features spectacular outdoor gardens and exquisite frescoes, furnishings, and paintings within its walls. Originally constructed in 1764 as a replacement for the Alcázar castle, which had been destroyed by fire three decades earlier, this magnificent edifice is a must-see attraction for anyone visiting Madrid. Nearly the entire palace is open to the public, including the Armoury and Pharmacy.

For sweeping views over Shanghai, visit this 492-metre skyscraper. Also known as SWFC or "the bottle opener", this second-tallest building in Shanghai features an indoor observatory from the 94th to 100th floors. Walk across the impressive Sky Bridge on the 97th floor and experience the tallest observatory in the world on the 100th floor.

The eclectic Thyssen-Bornemisza Museum complements the Prado and the Reina Sofia with works such as 17th-century Dutch paintings, impressionism, Russian constructivism, and pop art, amongst other styles.