Officials of the Song dynasty documented a "guest star" bright enough to be visible in daylight for weeks, recording its position and duration with remarkable precision. Centuries later, astronomers identified the remnant of this explosion as the Crab Nebula, one of the most studied objects in the sky and a cornerstone of modern astrophysics.

Commissioned by King Manuel I, da Gama's expedition sought to break the Venetian and Arab monopoly on spice trade by finding an all-water route to Asia. His eventual arrival in Calicut in 1498 would open an age of European maritime empire, reshaping global trade, colonization, and conflict for centuries.

Meeting in Philadelphia, delegates approved the final text of Thomas Jefferson's draft, transforming a rebellion into a formal assertion of nationhood. Though most signatures came later, and the vote for independence had actually occurred two days earlier, July 4 became the date printed on the document and forever fixed in American memory as the birth of the United States.

Gaspard-Félix Tournachon, known as Nadar, pursued the seemingly impossible task of photographing the earth from a hot-air balloon using cumbersome wet-plate equipment. His efforts, refined through the mid-1850s, established the foundations of aerial photography, later adopted for military reconnaissance, urban planning, and archaeology.

Under the Treaty of Manila, the US relinquished sovereignty over the Philippine Islands, fulfilling a promise made a decade earlier in the Tydings-McDuffie Act. The transition came after brutal Japanese occupation during World War II and years of guerrilla resistance, leaving the new republic to rebuild amid widespread devastation.

The new flag design, featuring five rows of six stars alternating with four rows of five, replaced the 49-star version used only briefly after Alaska's statehood. It has remained unchanged since, the longest-used design in American flag history, now flown for over six decades.

After the RPF, led by Paul Kagame, fought its way into Kigali, the interim government responsible for orchestrating the genocide against Tutsi and moderate Hutu fled the country. The rebel victory halted the mass killing but came too late for hundreds of thousands already dead, and it triggered a massive refugee crisis as millions of Hutu fled into neighboring Zaire.