Cryptocurrencies like Bitcoin run on blockchains- a shared and immutable list of transactions that allows convenient tracking and recording.
Ethereum blockchain
News reports suggest that the US Securities and Exchange Commission has lodged an inquiry into Ethereum Foundation and plans to reclassify Ether as a security.
Ethereum briefly hits the $4k level ahead of the planned Dencun upgrade. With the Dencun upgrade, it's expected that the blockchain will become more efficient.