1) The first smartphone, the IBM Simon, was introduced in 1992 and featured a touchscreen, email capabilities, and apps such as a calendar and calculator.

2) The Mongol Empire, under the leadership of Genghis Khan, became the largest contiguous empire in history, spanning from Asia to Europe.

3) The Mona Lisa, painted by Leonardo da Vinci, is one of the most famous and valuable artworks in the world.

4) 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.