The link to the challenge is shown below:
It is now Day 21, and the letter is 'U", Unobtanium
The "Unobtanium" symbol looks like this:
Source: https://coinmarketcap.com/currencies/Unobtanium/
Letter U: Unobtanium
It is now Day 21, and the letter is 'U", Unobtanium
The "Unobtanium" symbol looks like this:
Source: https://coinmarketcap.com/currencies/Unobtanium/