Borgholm Castle, a stunning silhouette against the Öland sky, stands as a testament to Sweden's rich tapestry of history. Known as Scandinavia's most captivating ruin, this architectural chameleon has evolved through the centuries, echoing tales of regality and resilience. Though now a poignant shell due to the devastating fire of 1806, it continues to guard the stories of its past, from medieval might to Renaissance elegance.

Ain Zubaidah stands as a testament to ancient engineering, a water system commissioned over 1,200 years ago by Zubaidah, wife of the Abbasid Caliph Harun al-Rashid. Moved by the plight of pilgrims, she ordered the creation of a complex network to channel water from the Al-Kar mountains to the holy sites of Makkah. This 35-kilometre feat of engineering combined underground channels, surface aqueducts, and deep reservoirs, some reaching 40 metres underground, to traverse the arid landscape. Though time has left much of the original structure in fragments, sections have been restored, including a major renovation in the 1920s. The system's scale remains awe-inspiring, with its gentle gradients, 132 inspection chambers, and strategic storage tanks. Today, visitors can explore remnants of the conduits in the foothills around Makkah, a tangible link to a visionary project that sustained generations of pilgrims.

The Kaaba, the cubic structure at the heart of Mecca's Al-Haram Mosque, is the holiest site in Islam and the focal point towards which Muslims worldwide pray. It stands at the centre of the Mataf, the courtyard where pilgrims perform the Tawaf, the ritual of circumambulation. Embedded in its eastern corner is the Black Stone, a revered relic set in a silver frame, which pilgrims strive to touch or kiss as part of the rites. As the direction of prayer and the ultimate destination of the Hajj pilgrimage, it represents the spiritual axis of the Muslim faith.

For a taste of Japanese history, this is where you’ll find Japan’s largest collection of Asian artefacts. The main gallery, Honkan, displays an impressive assortment of swords, masks, wood-block prints and kimonos while other must-see features include the 7th-century bronze-seated Buddhas in the Horyu-ji Homotusukan.