In February 2019, Tibet's Everest Base Camp was further closed to visitors to allow for continued cleanup and environmental restoration efforts, begun in 2018 with the removal of eight tonnes of garbage. Tourists are restricted to day visits and can only go as far as Rongphu Monastery, 3km from the technical climbing camp. The tent camps were closed indefinitely.
Everest Base Camp (5150m) was first used by the 1924 British Everest expedition. Tourists aren't allowed to visit the expedition tents a few hundred metres away, but sometimes (if it's open) you can clamber up the small hill festooned with prayer flags for great views of the star attraction. Most people have their photo taken at the ‘Mt Qomolangma Base Camp’ marker, which indicates that you are at 5200m above sea level. (Other measurements have it at 5020m or 5150m.)
Note that you can get mobile phone reception at Base Camp, and many of the tent hotels have wi-fi. WhatsApp a friend. They’ll be thrilled.