This is the amount sent
overall in the block, with all the transactions in it. That means that the one with 37,000 BTC in it was all of the 2,291 transactions in the block.
There have been way crazier transactions in the past, such as
this one (sending 194,993 BTC a long time ago).
If you're talking about it being unusual that the mean average amount sent in a transaction is a large amount, that's just because fees are very high. Microtransactions are impractical, so people send large ones instead because Bitcoin is good for that (and very secure).