Sierra Leone’s capital Freetown and other cities have been suffering blackouts for weeks. It’s disrupted hospitals and daily life for many. Most of Freetown’s power comes from a Turkish ship floating off the country’s coast - and they’ve massively reduced electricity supply to the city because of unpaid bills. Karpowership is one of the world's biggest floating power plant operators, with several African states relying on it for electricity.

BBC journalist Chimezie UcheAgbo explains where Sierra Leone gets its power and what’s causing the blackout. Fatmata Gassim (19), an engineering student in Freetown, tells us how the blackout has affected her. We also hear about power outages in Ghana (from the BBC’s Favour Nunoo in his car) - and the rocketing cost of electricity in Nigeria. Irene Leigh (23) sends us a message about how her company, EasySolar, is helping people in Sierra Leone find alternative ways to get their power.

Instagram: @bbcwhatintheworld WhatsApp: +44 0330 12 33 22 6 Email: whatintheworld@bbc.co.uk Presenter: Hannah Gelbart Producers: Julia Ross-Roy, Emily Horler and Mora Morrison Editor: Verity Wilde

President Biden has just signed a law that says TikTok’s Chinese owner, ByteDance has nine months to sell the app or it will be blocked in the US. We hear what TikTok users in the US think about the ban - and how it would affect them. Liv McMahon from the BBC tech team explains why the US government has done this, how TikTok has responded - and why it won’t be easy to sell the app. And the BBC’s Kerry Allen describes the origins of TikTok in China and the Chinese reaction to the ban.

Instagram: @bbcwhatintheworld WhatsApp: +44 0330 12 33 22 6 Email: whatintheworld@bbc.co.uk Presenter: Hannah Gelbart Producers: Julia Ross-Roy, Benita Barden and Mary Isokariari Editor: Verity Wilde

Nuclear weapons have been back in public conversation recently - partly due to rising tensions between Iran and Israel. Outside of the news, they have also been featured a lot in films and TV shows. (Think Oppenheimer and Fallout).

But, what are nuclear weapons? And is it likely they’ll be used again? Or, have we learnt from what happened in Hiroshima and Nagasaki?

The BBC's security correspondent Gordon Corera explains. We also hear from a nuclear studies student in Islamabad, Pakistan, about why young people should care about them.

Plus, Alex Rhodes from the team talks us through some nuclear close calls. This includes how the actions of one Stanislav Petrov could have saved us all.

Instagram: @bbcwhatintheworld WhatsApp: +44 0330 12 33 22 6 Email: whatintheworld@bbc.co.uk Presenter: Hannah Gelbart Producers: Mora Morrison, Alex Rhodes and Maria Clara Montoya Editor: Verity Wilde