Walƙiya – Mai ban sha'awa amma mai haɗari
Babban abin mamakin yanayin walƙiya da tsawa ya kasance abin birge ɗan adam tun daga lokacin.
A cikin tatsuniyoyin Girka, ana ganin Zeus, Uban Alloli, a matsayin mulkin sararin sama wanda galibi ana hasashen ikonsa kamar walƙiya. Romawa sun danganta wannan ikon ga Jupiter da kabilun Jamusawa na nahiyar zuwa Donar, wanda Jamusawan Arewa suka sani da Thor.
Na dogon lokaci, babban ƙarfin hadari yana haɗuwa da ikon allahntaka kuma mutane suna jin tausayin wannan ƙarfin. Tun daga Zamanin wayewa da ci gaban fasaha, wannan kyan gani na sama ana binciken kimiyya. A cikin 1752, gwajin Benjamin Franklin ya tabbatar da cewa abin da ya faru na walƙiya cajin lantarki ne, Walƙiya - Mai ban sha'awa amma mai haɗari.
Kimanin hasashen yanayi ya ce kimanin walƙiya biliyan 9 ke afkuwa a kowace rana a duniya, mafi yawansu a wurare masu zafi. Koyaya, adadin lalacewar da aka ruwaito sakamakon sakamakon walƙiya kai tsaye ko ta kai tsaye yana kan hauhawa.