Evidence of past Tidal Waves visible from SpaceUse Google Maps http://maps.google.com/maps .
Why? Your life may depend on it.
View the coast lines of the world near to you and see what evidence is glaringly obvious. For example, sand was washed ashore and left in a hollow drop shape as the excess water drained back into the sea.
In the case of the north coast of Queensland the sand hills are up to 20 kilometres long! The width of this event is several hundred kilometres. Unless the event was truly catastrophic, given the increase in sea level say 125 metres due to the ending of the last ice age C.10,000 years ago, the evidence only goes back those 10,000 years. There may have been smaller events in that time but they may have been washed off by the "big one".