UPDATE: This item is now found under the Logs menu. The events that you can sort by has been expanded as well. Under 'Event Type' it is possible to sort by: Access Rights, Affiliate Tracking, Billing events, Emails sent, Pages Accessed and Login.
Note: The activity log can get quite large over time. The more traffic you have, the more quickly it will grow. Consider using the activity log cleanup tool to automatically remove log entries older than a certain number of days. Read this article to learn more about configuring activity log cleanup.