Five of the best free things to do in London this weekend

April has arrived, spring is in full force, and Londoners are heading outside with a vengeance: soaking up some rays in their local park, flocking like geese to canal-side cafés, or desperately trying to take non-naff photos of cherry blossom (good luck).

Still, there’s even more fun to be had indoors if you know where to look. And best of all, plenty of it is totally free. From five-star photography exhibitions to free croque monsieurs, here are five brilliant free things to do this weekend.

Get a free croque monsieur at Balthazar

Fun fact: croque monsieur basically means 'Mr Crunch' in French. It's not a serious food. So why not get a bit frivolous this weekend and treat yourself to a free ham and cheese toastie at Balthazar. All you have to do is turn up in a Breton stripe top (string of garlic and beret optional) and you'll get your hands on a delicious croque monsieur for zero pounds and zero pence. Délicieux.

Balthazar, WC2B 5HZ. Sat Apr 5 - Sun Apr 6, 10am - 4pm. 50 available per day, first come first served.

Check out the National History Museum's brand-new gallery

It's not every day that NHM opens a new gallery. In fact, it's been 10 years since the last one was unveiled. So don't miss their brand new free exhibit, the optimistically-named Fixing Our Broken Planet. Over 200 specimens will tell the story of climate change in a fun and approachable way. You can discover what a whale's ear wax can tell us about rising sea temperatures, learn how local lichen can tell you about air pollution, or even calculate the carbon footprint of your blameless family pet.

Natural History Museum, SW7 5BD. From Apr 3. Free.

Catch the final weekend of Peter Hujar at Raven Row

If all this bright sparkling sunshine is starting to feel a bit oppressive, escape into the dimly-lit depths of New York's lost queer scene at this stellar retrospective. Artist Peter Hujar photographed underground luminaries including Candy Darling and William S. Burroughs: here, those famous portraits sit alongside moody, grimy Manhattan street scenes and grave photographs that memorialise a social world decimated by the AIDS crisis. Read Time Out's five star review here. 

Raven Row, E1 7LS. Until Sun Apr 6. Free.

Join a second-hand shopping social

Even in the era of Depop and Vinted, any self-respecting secondhand lover knows that rifling through charity shop rails is a stellar way to spend your weekend. And this Saturday, Traid Walthamstow is making browsing extra-fun with a mini party to celebrate their recent makeover. There'll be free drinks courtesy of Dalston's Sodas, Toast Brewing and Renegade Urban Winery, plus DJs from Farrago so you can check your new ’fits are dancefloor ready. Plus, an in-store embroidery workshop from 12:30pm-3:30pm will help you make sure your clothes are truly one of a kind.

Traid Walthamstow, E17 7JY. Sat Apr 5. Free.

Dance at a free R&B day party

Bop to three decades of R&B sounds at Pop Brixton's free party, which starts at 5pm. This creative space has a courtyard that's full of bright murals, fairylights and tropical plants: perfect for enjoying the sunny, nostalgic sounds of artists including Ciara, Lauryn Hill and TLC. Just get there before sunset: there's an entry fee after 9pm.

Pop Brixton, SW9 8PQ. Sat Apr 5. Free.

Willing to splash some cash? Check out our comprehensive roundup of the best things happening in London this weekend

And start planning a great spring with our preview of ten unmissable London events coming up over the next few months