WHY THE WORLD MISSED THE GREATEST MONEY MAKING OPPORTUNITY EVER?

Bitcoin is so 2017. If you missed out as the virtual currency soared from $1,000 to over $19,000, here are five other digital assets you can jump into with your holiday cash and try to ride the next wave...or lose it all in the next crash.

Several alternative currencies have also seen significant movement in the past year, rising anywhere from 600 to 37,000 percent. BUT BEFORE YOU BUY, DO YOUR RESEARCH.

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The first thing to remember is that you can buy a fractional piece of almost any cryptocoin for just a few bucks — no need to shell out thousands of dollars for a full bitcoin, for example.

Some digital assets are designed to be actual currencies for conducting transactions. Others are "tokens" issued by specific companies as a way to raise money. The value of the token may rise or fall based on how well their product is doing... or they may just get bought up in a speculative spree.

"The same rules apply for speculating in cryptocurrencies and tokens as every other investment class," said Nick Colas at DataTrek Research, an analyst who's been covering cryptocurrency for over four years. "You have to know who is in charge, what problems the product is supposed to solve, what competition exists," and why anyone would want to use the underlying product.

Can't answer those questions? Does the idea of seeing your nest egg swing up and down double-digit points within a few hours give you indigestion? Then maybe stick to low-fee index funds. Otherwise, buckle in. Prices and percentages are rounded.

RIPPLE (TOKEN)

Jan. 1, 2017 close: Less than one cent

Jan. 1, 2018 close: $2.40

Rise: 37,400 percent

Ripple is designed to be a cheaper, faster, and more direct way to send money around the world. That has led to some big banks testing it out. But after hovering below a dollar for a months, the price suddenly shot up in late 2017 on the back of a South Korean word-of-mouth buying surge. Now it's in the top 10 of all cryptocoins by market capitalization.

IOTA (TOKEN)

June 13, 2017 close: $0.60 (launched in June)

Jan. 1, 2018 close: $4.00

Rise: 570 percent

We've heard about how "Internet of Things" devices will one day talk to each other. But how about if they also pay each other? "One day, when your fridge orders more milk, it may pay with IOTA," said Colas. The bulk of the token's jump occurred in November when the company announced it was starting a data marketplace with 35 participating companies, including Microsoft and Samsung.

MONERO (COIN)

Jan. 1, 2017 close: $14

Jan. 1, 2018 close: $360

Rise: 2,470 percent

It's like bitcoin, except even more anonymous. That's made it the new coin of the realm for technophiles and dark web transactions.

VERTCOIN (COIN)

Jan. 1, 2017 price: $0.03

Jan. 1, 2018 price: $6.80

Rise: 22,500 percent

One of the criticisms of bitcoin is that it's supposed to be deregulated and decentralized. But "minting" or "mining" more bitcoins requires using increasingly faster and more expensive computers to solve more complex math problems. That puts more power in the hands of those who have the time and money to run the mining systems, especially specialized machines whose sole purpose is mining. Vertcoin is a tweaked version of bitcoin that its developers say is "resistant" to being exploited by some of these systems. That's drawn fans on the social link sharing site Reddit, and soaring popularity over the last year.

CRYPTOKITTY (APPLICATION)

True to the nature of the internet that birthed them, these speculative products are a little quirky. Case in point, "CryptoKitties," which are not tokens or cryptocurrencies themselves but a special kind of digital app that uses Ethereum, another cryptocurrency that was hot in 2017. They're sort of like Tamagotchis (remember those?) except you can breed them and create offspring that share qualities of both parents. Whether you think that's fun or frivolous, there's real money in the virtual toy. Over 10 of these digital felines have sold for over $100,000.

"This whole area is the Wild West," Colas told NBC News. "Many ICOs make the 1990s dot com boom stocks look like Blue Chip securities."