You have been chosen to participate in a selection process for a secret underground group. To make sure you're worthy, they test you with a series of devious puzzles. However, one in particular has you stumped...
The challenge you receive is as follows:
People aren't very good at observing things. We hope you are better.
To solve this challenge, you will need to inspect the contents of the link below:
We look forward to your success.
- The Underground Group
The solution is obvious once found, and requires no special skills to uncover.
But, of course, you need to keep your eyes and mind open...