At the Metropolitan Opera last spring, in a show called "The Exterminating Angel", soprano Audrey Luna sang a high A, setting a new record for the highest note ever sung at the Met. You might be more familiar with the phrase "High C", a very typical high note at the Met - the high A is several notes higher. And it's the first thing Luna sings in the show. She spent years working her voice up to that pitch. So we asked her how she did it.

The latest nasty security scourge plaguing the internet is cryptojacking. By running hidden code on a seemingly ordinary webpage, hackers and disreputable webmasters can highjack your CPU's processing power in order to mine cryptocurrency, line their own pockets, and kill your performance. Opera is now the first web browser with a built-in tool to fight off this practice - and hopefully it won't be the last.

Your browser might be doing someone else's dirty work behind your back, mining cryptocurrency for malicious individuals using your desktop or laptops to create the digital currency, which can potentially be exchanged for real cash. According to Wired, hackers have found a way to inject Javascript-based cryptocurrency mining software into compromised sites, borrowing your processing power (and slowing down your computer) to generate the cryptocurrency Monero.

While Chrome has won the crown as the most popular desktop browser, it's not the only game in town. Opera continues to add new features. Last year, it was the addition of an integrated VPN that won it headlines. This week, Opera released a new version. Codenamed Reborn, it allows messenger apps to reside within the browser without the need to install any extensions or apps.

Last year, Opera, the little browser that everyone seems to forget about, rolled out a free VPN. While it immediately ran into a security problem by leaking IP addresses, it's now been patched up, and is easily the simplest, cheapest and reasonably private way to access a VPN right now. It does come with a slew of caveats though.

When Google originally launched Chrome, it made a point of promoting the browser's performance over its competitors. But that was almost 10 years ago and both Chrome and Apple's desktop OS have changed... a lot. Given this large chunk of time, has Chrome remained on top of the pile when it comes to grunt? The answer is "mostly".

Chrome/Firefox/Opera: When Privacy Badger launched a few years ago, it was already a great tool to block third-party trackers, speed up the web and stop sites from watching your every move while you browse. The latest version is a huge improvement, in almost every way.

Windows/Mac/Linux: A few months ago, Opera launched its own free, built-in VPN, but you could only get it if you manually enabled it in the dev version of the browser. Now, it's available for everyone in the stable version of Opera.

If you've been on the lookout for a decent VPN on Android that won't break the bank, your wait is over. After releasing on iOS earlier this year, Opera's popular free and unlimited VPN is finally available for Android devices.

Chrome/Opera/Safari/Firefox (Beta): It's been a while since we highlighted Gmelius, the add-on that cleans up Gmail's interface. It's grown since then, and now has features to send emails later on a schedule, snooze them, bundle in useful reminders and block email trackers.

Windows/Mac/Linux: Opera has rolled out another update to its browser, this time introducing a power saver mode that supposedly gives you a 50 per cent boost in battery run time.

iOS: Virtual Private Networks (VPNs) are often a costly affair, but Opera, the company best known for its browser, released a free, unlimited VPN for iOS today that allows you to access the internet securely from a variety of locations.

Last week, Opera added a VPN to the dev version of its browser, which was certainly good news. The bad news is that unlike the more robust VPNs it tries to replace, it leaks data that should be encrypted all over the place, namely your private IP address. Here's how to fix it.

Windows/Mac/Linux: Opera users just got a free, unlimited VPN that you can use to encrypt your data or get around location-based restrictions on content. It's currently in the dev version of Opera, but turning it on is as easy as flipping a switch.

Opera’s latest mobile browser concentrates on speed and an improved Android experience, as it tries to double its Android market share.

Chrome/Firefox/Opera: Using HTTPS is essential for keeping your personal information safe, especially when browsing on public Wi-Fi. Free extension HTTPS Everywhere recently updated with thousands more rules, ensuring HTTPS is enabled on as many sites as possible.

Opera may have switched to Google's Chromium to handle the heavy-lifting of the web, but that doesn't mean the browser isn't doing plenty of work to separate itself from Chrome. It comes with experimental features you can activate if you're feeling brave, including the recently-added "video boost" for the software's "Turbo" option.

A common pitfall of internet use is clicking on broken links that lead nowhere. Sometimes dodgy coding is to blame, other times the linked-to webpage or subsite has been removed. Whatever the cause, it can be bloody annoying. Occasionally though, the website in question will take some of the sting out by turning its 404 error page into an interactive experience. Here are 15 of the best; from digital art canvases to full-blown text adventures. (We've also included broken links so you can play them yourself.)

VPNs are great for security, but one of the big reasons many people use one is to mask or change their IP address. This lets you get around location-based restrictions on content, or check if your provider is throttling your connection. Unfortunately, a new security flaw can reveal your real IP address to prying eyes, even if you're using a VPN, and it's easy to exploit. Here's how it works and what you can do about it.