1. Which is longest river in world ?

Answer: Nile, Africa

2. Which is Largest Dome in World ?

Answer: St. Peter's Basilica (Rome)

3. Which is the Densest populated State of India ?

Answer: West Bengal

4. Which is the largest desert in India ?

Answer: Thar (Rajasthan)

5. Which is the biggest museum in the world ?

Answer: British Museum, London

6. Which is the highest waterfall in the world ?

Answer: Angel, Venezuela

7. Which is highest dam in world ?

Answer:

Jinping-I Dam - 305 m (1,001 ft) in China on Yalong river.
Second Highest is Nurek Dam 300 m (980 ft) Tajikistan on Vakhsh river.