1) 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.

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

3) The word "piano" contains three vowels: I, A, and O.

4) The world's first credit card was introduced in 1950 by Diners Club.