It's been a dramatic month in terms of the sea - the dreadful, destructive tsunami wiped out entire towns on the east coast of Japan. The images will stay in my mind for ever, although I think certain news channels overdid the "wall of water" video footage - non-stop 24-hours-a-day of huge waves, floating cars and upside-down houses can lose their shock value after a while, until you suddenly remember you're not watching a disaster movie or a video game, but people's homes - and lives - being washed away. The sea's behaviour was also unusual, although in a far less aggressive way, on Saturday here in Andalucia. The moon came closer to the earth than for the last 19 years on Saturday night - did you see the "supermoon" shining ethereally bright? The skies here were perfect, crystal clear - causing extremely low tides that morning. In Cadiz city, the sea went so far out on La Caleta beach that people could walk around the back of the Castillo San Sebastian, normally accessible only by a causeway across the bay, and much further out. Other city beaches which saw out-of-season crowds were La Victoria and Santa Maria del Mar. Thousands also turned out to see the island castle of Sancti Petri near Chiclana de la Frontera, normally divided from San Fernando's Punta Boqueron beach - whose regular appearance is a narrow finger of sand - by the sea. The islet almost became joined to the land opposite, thanks to the bajamar. Massive traffic jams formed from as early as 8am (that's very early for Spaniards on a Sunday), as people tried to get to the beaches of Cadiz to see the historic sights of normally submerged areas open to public view. It was a holiday atmosphere as everyone marvelled at the natural wonders, and immortalised the moment on their cameras. Andalucians love the beach - it's impossible to walk on the sand in August, there's no space left between the towels of sun-worshipping Spaniards - but this time, they were fully dressed and upright. Scientists were also out in force to study subaquatic plants which hadn't been seen for years, and the low tide also caused new water to be washed into the Parque Natural Bahia de Cadiz, providing it with fresh nutrients for the waterfowl which inhabit the area. Sometimes we can witness the force of nature, without it causing untold chaos and tragedy.