# Block Detail Page

Each Aptos block contains both user transactions and special system transactions to *mark* the beginning and end of the transaction batch. The number of transactions within a block varies depending on network activity and a configurable maximum block size limit. As the blockchain becomes busier, blocks will likely contain more transactions.

Specifically, there are two system transactions:

1. `BlockMetadataTransaction` - is inserted at the beginning of the block. A `BlockMetadata` transaction can also mark the end of an [epoch](https://aptos.dev/concepts/blocks#epoch) and trigger reward distribution to validators.
2. `StateCheckpointTransaction` - is appended at the end of the block and is used as a checkpoint milestone.

Here is how the details are displayed on aptscan.ai

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***Overview section:***

* **Block heigh**t: the block position on the chain
* **Version**: the transactions that are included in the block
* **total**: the number of transactions inside the block
* **Committed timestamps**: the timestamp that the block got appended to the chain
* **Proposer**: block leader&#x20;
* **Epoch**: represents a longer period of time in order to safely synchronize major changes such as validator set additions/removals
* **Round**: achieving consensus on a block of transactions and their execution results.

***Transactions section***:

* **version**: the transaction&#x20;
* **type:** type of transaction
* **age**: time recording of the transaction
* **Sender**: the account initiates the txn
* **Function**: the function of the txn
* **gas fee**: cost to run the txn