For the first time, the heads of the UK's spy agencies have faced questions from MPs in a public meeting.
MPs questioned the spy bosses about their methods of collecting information using the internet and phones.
The spy chiefs defended what they do in their jobs, with head of MI5 Andrew Parker saying they look after "freedom and democracy".
Documents recently published in a British newspaper suggested US and UK spies tapped into millions of emails.
Now there's a big debate about how much we should know about the methods spies use to try and keep us safe.
It's not the first time a meeting like this has taken place, but it is the first time that it's been done publicly.
The three agencies under the spotlight are MI5, MI6 and GCHQ.
The director of GCHQ is Sir Iain Lobban, the MI5 director general is Andrew Parker and the MI6 chief is Sir John Sawers.
Why is this happening?
Recently there's been a rise in concerns about governments spying on the public, and even the leaders of other countries.
This came about after Edward Snowden, who used to work for US spy agency the NSA, exposed details of American spy operations to the British media.
As a result of the information he gave to The Guardian newspaper many more spying claims have hit the headlines.
The leaks suggested the NSA had hacked the phones of several world leaders.
Angela Merkel, the German Chancellor, was outraged to hear claims that her phone had been hacked by American spies.