Uninvited guests?

Technical Details

Forum version : #phpBB3
Position : Founder
Concerned browser(s) : Safari
Who the problem concerns : Yourself
When the problem appeared : Last night
Forum link : ( link is hidden, you must reply to see )

Description of problem

I have created my first forum and am the only one with access at the moment as I am still designing it, yet last night I noticed that the "who is online" was showing myself (Admin) and some guests. These guests were listed as viewing the forum index. The number of guests fluctuated between two and seven for a while and they disappeared, and some appeared later too. I checked a couple of locations and one was in London and another somewhere in Germany.
What is going on?

Hello @Dollymixture,
Those guests usually are search engines bots/spiders/crawlers. It isn't something dangerous or suspicious.

Thanks for the swift reply and thanks.