Polkadot is an infrastructure platform with parachains networks (specialised blockchains) that are united in a single ecosystem. Polkadot has a Relay Chain without any smart contracts in its core to provide security to the entire ecosystem. This project was launched by Gavin Wood and it  launched the Ethereum team into rethinking about it’s the crypto’s structure and launch a platform that did away with the weaknesses found in the original one. The main feature of Polkadot is that applications are run on different blockchains and this allows to eliminate of a single bottleneck blockchain and to accelerate the transactions processing speed. 

To start working with Polkadot the developers must occupy a slot or a parachain that is released through an auction. So, developers must buy DOT tokens that are withdrawn from the market and blocked on specialised contract accounts until the end of a slot lease (six months, one or two years). Then these slots are auctioned again. For example, in November 2021 DeFi project Acala blocked 32.5 million DOT ($1.33 billion on that date). If DOT recovers from the current values and reaches peak values, the coin will bring in 760% of profit.