1) The world's oldest university, Al-Qarawiyyin, was founded in 859 AD and is located in Fez, Morocco.

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

3) The speed of light is approximately 299,792,458 meters per second.

4) 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.