1) The world's largest diamond, the Cullinan, was discovered in South Africa in 1905 and weighed over 3,000 carats.

2) The word "book" contains two vowels: O and O.

3) The Taj Mahal, located in Agra, India, is an iconic mausoleum recognized as a UNESCO World Heritage site. It was built in the 17th century by Emperor Shah Jahan as a testament to his love for his wife and stands as a masterpiece of Mughal architecture and a symbol of India's cultural heritage.

4) The first computer mouse was invented by Douglas Engelbart in 1964 and consisted of a wooden shell and two metal wheels.