On Sunday night, the ocean running alongside the East Coast Road in Chennai lit up with sparkling, luminescent water. Eyewitnesses were shocked and delighted to witness something so magical-looking and dubbed it 'sea sparkle'. But what they saw wasn't an undiscovered phenomenon - it's called bioluminescence and it actually occurs in many living organisms. That doesn't make it any less amazing though. Here's what 'sea sparkle' really is.