1914 followed by 1915
1914 (MCMXIV) was a common year starting on Thursday of the Gregorian calendar and a common year starting on Wednesday of the Julian calendar, the 1914th year of the Common Era (CE) and Anno Domini (AD) designations, the 914th  year of the 2nd millennium, the 14th  year of the 20th century, and the  5th   year of the 1910s decade. As of the start of 1914, the Gregorian calendar was 13 days ahead of the Julian calendar, which remained in localized use until 1923.  
This year saw the beginning of what became known as World War I, after Archduke Franz Ferdinand of Austria, heir to the Austrian throne was assassinated by Serbian nationalist Gavrilo Princip. It also saw the first airline to provide scheduled regular commercial passenger services with heavier-than-air aircraft, with the St. Petersburg–Tampa Airboat Line.