Melt down small amounts and use it to manufacture gold plated "ultra fidelity lossless" audio/video/network/iphone charger cables that you sell at \$100 - $500 a piece to pretentious fools. This actually gets you more than the market price for your gold!
You may not have 45 million dollars at once, but you'll have a steady income for many years, and as a bonus, you'll have 99 bars of gold left in case of apocalypse or something.
Alternatively, restamp some of the bars with a Swastika, hide them in some cave in Germany and then "find them". If you get a 1% finder's fee, you're still rich.
Edit: This answer has drawn a lot more attention than expected, so I will try to improve the quality some.
The original question outlines the problem with authorities taking a dim view of anyone trying to sell a huge amount of gold from an unknown source.
Unloading the gold in bulk to any shady people carries a serious risk too: They may well decide to betray you, lock you up and torture the location and source of your gold out of you.
Assuming you don't already know how to speak "Billionaire", you would look out of place and suspicious trying to pass yourself off as one or even as a representative for a rich guy trying to liquidate some assets, though that is still a realistic option (see user16295's answer for a better description of that) but there are better options.
Pawn shop road trip
Luckily for you, you live in the age of StackExchange and more importantly, 3D printing with gold.
It will take some setup and preparation, but you don't have to try and sell whole bars, you can instead mass-print jewelry and age it a bit (get some small bits of dirt stuck in the recesses).
The second part of the prep is setting yourself up as some kind of travelling salesman or freelancer, plan some trips to distant states/cities and start doing rounds of the local pawn shops and gold buying outfits (don't google them from your own internet connection obviously).
Never sell more than a "grandma's inheritance" at once. Accept cash only, but walk away from too low a price. You're not a thief trying to fence stolen goods after all. It will take a long time, but you can have fun along the way and get see more of the world.
Hook up with someone important
This is a lot more complicated, but you did become a hero in the course of your fantasy world adventure, so maybe your skills are up to it. The goal here is to make someone with the resources to buy your gold believe that you are well-connected, so that they will refrain from taking your gold and life for fear of the consequences.
Your target will be some rich person that can unload the gold again, no questions asked. This means you'll probably end up with some Arab billionaire who's looking to gold-plate his newest yacht or wants to work with foreign businessmen on a prestige project. Getting into the oil and construction industries (as a contractor) will be difficult, but if you can manage it, they are your best options. Alternatively, you cash in some of your gold through the pawn shop route so you can spend enough to pose as an investor in any field currently popular over there.
Your ticket to a deal will be an introduction by someone the target highly regards, so once you have some way in, network like crazy. The best stepping stone is likely a fellow countryman, both because it's easier to connect with them and because your real target will assume you know each other from business or private life "back home". Hang out in the expat favorite bars, find out who's only tech and who's a dealmaker. Get yourself invited to parties and events, etc.
Once you have a promising link, investigate their business partners. Select the likeliest prospect and have a good story ready. "I need to sell $45 million in gold" is not a good story in most cases." Investment opportunities work best, so tell your newest BFF about your investment plan while you have some drinks and ask him if he knows about "this guy Aziz" and if they can introduce you.
Make your pitch to the prospect and if he's interested, tell them that you would love to get into more detail and schedule a meeting some weeks ahead. Apologize profusely for the delay and explain you need the time to unwind another deal and free up your money. Pray for the guy to bite and ask about the details, at which point you mention the gold and see what happens.
Note: All this assume you are a) male and b) of an age to pose as a business man. If you are female, all this will not work. If you also happen to be a hot blonde, then you can skip all the socializing and just straight up ask the first crazy-colored supercar driving guy you spot to buy all your gold.