A Tangle is an innovative distributed ledger technology that uses a directed acyclic graph (DAG) structure instead of the traditional blockchain design. This unique architecture represents a significant departure from blockchain's linear chain of blocks, as transactions in a Tangle are interconnected in a web-like pattern.

The key feature of a Tangle is its validation mechanism: when a user wants to make a new transaction, they must first validate two previous transactions in the network. This creates a self-sustaining system where each participant actively contributes to the network's security and consensus. As more transactions join the network, they form a complex web of interconnected verifications, with newer transactions indirectly confirming older ones through this validation process.

This structure offers several advantages over traditional blockchain technology. First, it enables parallel processing of transactions, potentially allowing for infinite scalability. Second, since each user participates in validation, there's no need for miners or validators, eliminating transaction fees and making it particularly suitable for micropayments and Internet of Things (IoT) devices.

The Tangle architecture also addresses the bottleneck issues common in blockchain systems. Rather than forcing all transactions through a single chain, the Tangle allows multiple transactions to be processed simultaneously. As network activity increases, transaction confirmation speeds can actually improve, contrary to blockchain systems that often slow down under heavy load.

However, the Tangle design isn't without challenges. The security of transactions depends on the network's size and activity level, as a sparse network could be vulnerable to attacks. Additionally, achieving distributed consensus in a DAG structure presents unique challenges compared to blockchain's more straightforward consensus mechanisms.

Despite these challenges, the Tangle represents an innovative approach to distributed ledger technology, offering potential solutions for scalability and fee issues that have long plagued traditional blockchain systems. It's particularly promising for applications requiring high throughput and minimal transaction costs.