1) The Sydney Opera House, situated in Sydney, Australia, is an iconic architectural masterpiece and a UNESCO World Heritage site. Its unique design, resembling sailboats or shells, has made it one of the most recognized and photographed landmarks in the world.

2) International relations encompass the study of relationships between nations, including diplomacy, treaties, and foreign policy. It examines the interactions and dynamics among different countries in the global arena.

3) In Aztec mythology, the god Quetzalcoatl is associated with the planet Venus, which was seen as a celestial embodiment of his power. His connection to Venus also ties into his association with fertility, renewal, and the cycles of life, as Venus is associated with beauty, love, and abundance.

4) The first commercial GPS (Global Positioning System) was launched in 1989 and provided accurate positioning and navigation capabilities to users worldwide.