Let explain how I do this
I will take the "Pizza Block" to illustrate.
On 2010, may the 22nd, a bitcoin developper (Laszlo Hanyecz) bought a pizza with 10 000 BTC.
This is widely recognised as the first real-world transaction with bitcoin.
As the Blockchain is public, we can find the block that contains this transaction.
I call it the "Pizza block", it is at height 57035.
It contains 2 transactions, the pizza and the reward for the mining.
You can explore the block
here.