Calendar: Week of June 17 On Monday, the 50th International Paris Air Show opens to trade groups and the press, with rivals Boeing and Airbus both expected to announce orders for their latest aircraft. First flight of Airbus A350 reopens wide-body race World air fleet to double in 20 years, Boeing forecasts On Tuesday, President Obama heads to Berlin, following the conclusion of the G-8 Summit of world leaders in Northern Ireland. Wednesday is "Juneteenth" . . . a celebration of the end of slavery. A statue of abolitionist Frederick Douglas is due to be unveiled at the Capitol. Ga. school used slavery analogy to teach math Universities and theaters partner on new performances about Civil War Slaves, freedmen spied on South during Civil War Examining the faces of emancipation Jefferson's irony: Voice of liberty, slave owner On Thursday, Jennifer Lopez receives the 2,500th star on the Hollywood Walk of Fame. Jennifer Lopez: A design for living Friday is the First Day of Summer (in the Eastern and Central time zones, at least), with the solstice occurring at 1:04 a.m. Eastern Daylight Time. Because of the time difference, Summer starts late Thursday night in the Mountain and Pacific zones. Stonehenge a monument to unity, new theory claims And Saturday marks the 75th anniversary of heavyweight Joe Louis' fabled knockout of German boxer Max Schmeling in 1938. German boxing great Schmeling dies