Forming a chemical bond releases energy and therefore is an exothermic process. Exothermic reactions usually feel hot because it is giving heat to you. Endothermic-a process or reaction that absorbs energy in the form of heat. Breaking a chemical bond requires energy and therefore is Endothermic.
karma level 71199. The Seikan Tunnel is a 53.85 km (33.46 mi) railway tunnel in Japan, with a 23.3-kilometre (14.5 mi) long portion under the seabed. Track level is about 140-metre (460 ft) below seabed and 240-metre (790 ft) below sea level. It is the longest undersea tunnel in the world, although the Channel Tunnel between the United Kingdom and France has a longer under-sea portion.
If you have ever tried holding your breath while traversing a tunnel, we would recommend not trying while driving through this one. The Laerdal Tunnel located in Norway is the world's longest road tunnel and its designers have taken extra detail in making the drive especially beautiful. Stretching a total length of 24.51 km the roadway stands as the final link of European Route E16.