TODAY | December 17, 2013
>> we want to take a turn now and head to paris and the largest collection of jewelry that has ever been displayed. michelle kozinski had the pleasure of checking it out.
>> reporter: diamonds, so many diamonds. a collection that makes your head spin as well as the tiara on it.
>> i think it's fascinating for people because it's quite magical.
>> reporter: the collection by cartier is the largest ever assembled, not just jaw droppingly huge creations. the biggest was actually made for a dude. the better to be seen and admired from your elephant. but also kate middleton 's wedding tiara. the queen's favorite broach. grace kelly 's engagement ring . liz taylor 's necklace. walla simpson's flamingo. flakneighborin snakes, crocodiles. a gold umbrella handle. and a diamond encrusted comb for the best hair days. how do you even secure something like this? this must be like the most locked down location in paris right now.
>> it is. the jewelry is safe.
>> reporter: so i should empty your pockets now? i won't get the away with it, will i. for good reason. there was the biggest jewel heist ever in cannes. they calmly nabbed more than $100 million worth of precious gems. and he grabbed another bag before walking away on to the biggest street. do you think it was an inside job?
>> i would be surprised if not.
>> reporter: why?
>> because it's hard.
>> reporter: just this year, 40 jewelry robberies around paris alone and thieves are far less professional than in the past.
>> thing in the world you can't resist.
>> reporter: that's grace kelly and here is her jewelry. security had to get creative. plus synthetic d willna. engineered to glow. look at the difference between my hand that wasn't sprayed and the one that was. it stays on you for months traceable right back to where it was sprayed from. jewelers willing to do what they can.
>> it's a priceless collection. it will never be possible to replace any of those.
>> reporter: to protect what has been a bright shiny, far too easy target. for "today," michelle kozinski, nbc news, paris .
>> i have to get would not of those imagi one of those magic lights to shine on you see if you're guilty.
>> they're gorgeous.
>> there were some really pretty pieces there.
>> i liked the jade letter opener.
>>> coming up, do you want