Investors poured $30 billion into the crypto industry in 2021, more than in all previous years combined.

The massive sum is nearly four times more than the $8 billion that investors gave to companies in the digital money space in 2018, according to Bloomberg News, which cited figures from PitchBook Data, a financial software and data provider. And about $7.2 billion of the $30 billion pumped into the crypto space in 2021 came from U.S.-based investors.

As crypto became mainstream in 2021 many companies successfully attracted investors looking for the next big thing. Crypto exchanges, startups dealing with digital collectibles, and cypto-enabled gaming were all areas of the industry that secured high-profile multimillion- and even billion-dollar investments.

The crypto derivatives exchange FTX raised $1 billion in a July funding round, making the two-year-old company a major competitor for other large cryptocurrency exchanges such as Coinbase and Binance.

Investor money also found its way into the previously niche sectors of metaverse platforms and crypto-enabled “play-to-earn” games this year, in which users can earn cryptocurrency for playing. Sky Mavis, creator of the play-to-earn game Axie Infinity, raised $150 million on a $3 billion valuation in October.

The increasing interest in the metaverse, which is the blanket name for a part of the internet made up of a handful of platforms that include digital entertainment and business opportunities, has also spurred multimillion-dollar investments in the space. The metaverse platform Sandbox raised $93 million in a SoftBank-led round in early November.

In the NFT space, artists, Fortune 500 companies, and public figures like Quentin Tarantino have taken advantage of the new technology to sell digital pieces of art or other collectibles for tens of millions of dollars, which has helped attract interest from investors for the third-party exchanges arbitrating those kinds of sales.

OpenSea, the largest NFT exchange, raised $100 million in a July funding round led by Andreessen Horowitz that valued it at $1.5 billion. In November, the Information reported that the exchange was fielding offers valuing it at $10 billion or more.