President Donald Trump has called off his planned summit with North Korea’s Kim Jong-un. So now what? Also, as the Trump administration considers whether to impose new tariffs on auto imports, we look back at the effect US tariffs on imported solar panels have had on the renewable energy sector. Plus, you may have heard about the sinkhole that appeared on the White House grounds. We’ll get an explanation of why sinkholes happen, and how best to deal with them.