user: Why is the Cave of the Crystals or Giant Crystal Cave closed to the public?

assistant: The conditions in the cave are not hospitable, extreme heat and humidity, sharp slippery crystals are lethal for humans.

user: Please give me details about the French submarine Requin

assistant: The French submarine Requin was the lead ship of the Requin-class submarines built for the French Navy in the mid-1920s. Laid down in June 1922, it was launched in July 1924 and commissioned in May 1926. It was captured by Italian forces at Bizerte, Tunisia on 8 December 1942 and renamed FR 113. On 9 September 1943, it was recaptured by German forces. It was sold for scrap in Genes, Italy in 1944.

Design
78 m (255 ft 11 in) long, with a beam of 6.8 m (22 ft 4 in) and a draught of 5.1 m (16 ft 9 in), Requin-class submarines could dive up to 80 m (260 ft). The submarine had a surfaced displacement of 1,150 tonnes (1,132 long tons) and a submerged displacement of 1,441 tonnes (1,418 long tons). Propulsion while surfaced was provided by two 2,900 hp (2,163 kW) diesel motors and two 1,800 hp (1,342 kW) electric motors. The submarines' electrical propulsion allowed it to attain speeds of 9 knots (17 km/h; 10 mph) while submerged and 15 knots (28 km/h; 17 mph) on the surface. Their surfaced range was 7,700 nautical miles (14,300 km) at 9 knots (17 km/h), and 4,000 nautical miles (7,400 km) at 12 knots (22 km/h), with a submerged range of 70 nautical miles (130 km) at 5 knots (9.3 km/h).

user: What is Kraft Dinner?

assistant: Kraft Dinner, also referred to as KD, is a macaroni-and-cheese product by Kraft. It is essentially the same boxed macaroni-and-cheese sold in the United States, but referred to by a different name.