This workshop briefly describes the Gnosis chain, details why you should build on the Gnosis chain, and where to get resources. We also will introduce Hashi, a new EVM Header Oracle Aggregator, and how to build with Hashi. Hashi is an EVM Header Oracle Aggregator designed to facilitate a principled approach to cross-chain bridge security. The primary insight is that most bridge-related security incidents could have had a minimal impact if the systems relying on them had built in some redundancy. In other words, requiring messages to be validated by multiple independent mechanisms, rather than just one, is much more secure. Learn more about Hashi here: https://github.com/gnosis/hashi