Artist Christo attends the unveiling of his first UK outdoor exhibit, The London Mastaba, on the Serpentine Lake in Hyde Park, central London, Monday June 18, 2018. The sculpture consists of 7,506 horizontally stacked barrels on a floating platform in the lake. / BTA

An exhibition dedicated to the 30^th anniversary since the flight in outer space of Bulgarian cosmonaut Alexander Alexandrov was unveiled at the Bulgarian Academy of Sciences. Part of the collection are the original apparata and systems, which he and other cosmonauts have been using for their scientific experiments onboard the MIR orbital station. Photo: BTA

The Boris Hristoff House of Culture in Plovdiv opened a documentary photo exhibition entitled “August 21, 1968: the end of the Prague Spring”. The event is organized by the Czech Center in Bulgaria, with the cooperation of Honorary Czech Consulate in Plovdiv. Photo: BTA

The castle “In Love with the Wind”, built close to the village of Ravadinovo, not far from the seashore in Sozopol Municipality was given a certificate for membership in the World Tourist Alliance. It is the only one of its kind in Bulgaria and across the former socialist countries. Photo: BTA

Hundreds of tourists from across the country and from abroad are visiting the King Assen Fortress near the town of Assenovgrad, southern Bulgaria. This is the most interested and frequented site in that town. Photo: BTA