How did Hamas catch Israel by surprise?

The Israeli Government has one of the most well-resourced intelligence communities in the world, specifically tasked with preventing attacks from Hamas.So how did it fail to detect an operation that involved months of planning, meetings in multiple countries, and thousands of militants?This is part two in our series on the Israel-Gaza conflict.Subscribe to If You're Listening on the ABC Listen app.Catch up on our series about the Israel-Gaza conflict on YouTube: https://www.youtube.com/watch?v=OYJFHtTYc0g