Roman boat sinks 1700 years ago, remains undetected just 50 metres from a beach

We often think ancient shipwrecks are found deep in sea but what if one is found just 50 metres from a busy beach? A roman-era merchant ship had sunk 1700 years ago. The shipwreck lay just 50 metres from a now-busy beach near Mallorca, Spain but it went undetected...for centuries.