Article Detail Longest rail tunnel in the world ? Answer: Seikan Tunnel (Japan - 53.9 Km) Similar Questions : 1. Which is longest river of India Answer: Ganges 2. Which is the state largest by area in India ? Answer: Rajasthan 3. Which is the Densest populated State of India ? Answer: West Bengal 4. Which is largest Dam in World ? Answer: Three Gorges (China) 5. Which is the largest sea in the world ? Answer: Philippine Sea 6. Which is the lightest metal ? Answer: Lithium 7. Which is the Highest mountain peak ? Answer: Mount Everest (8,850 m) Read more from - Longest and Largest