var evts = [
  {
    "year": 1776,
    "name": "Declaration of Independence",
    "place": "North America",
    "require": ['Boston Tea Party', '']
  },
  {
    "year": 1787,
    "name": "Constitution of the United States of America",
    "place": "North America"
  },
  {
    "year": 1794,
    "name": "Whiskey Rebellion",
    "place": "North America"
  },
  {
    "year": 1803,
    "name": "Louisiana Purchase",
    "place": "North America"
  },
  {
    "year": 1815,
    "name": "Battle of New Orleans",
    "place": "North America"
  },
  {
    "year": 1823,
    "name": "Monroe Doctrine",
    "place": "North America"
  },
  {
    "year": 1829,
    "name": "Era of the Common Man",
    "place": "North America"
  },
  {
    "year": 1848,
    "name": "Treaty of Guadalupe Hidalgo",
    "place": "North America"
  },
  {
    "year": 1857,
    "name": "Dred Scott Decision",
    "place": "North America"
  },
  {
    "year": 1863,
    "name": "Battle of Gettysburg",
    "place": "North America"
  },
  {
    "year": 1876,
    "name": "Battle of the Little Bighorn",
    "place": "North America"
  },
  {
    "year": 1886,
    "name": "Haymarket Riot",
    "place": "North America"
  },
  {
    "year": 1896,
    "name": "Plessy v. Ferguson",
    "place": "North America"
  },
  {
    "year": 1902,
    "name": "Breakup of Northern Securities",
    "place": "North America"
  },
  {
    "year": 1915,
    "name": "Sinking of the Lusitania",
    "place": "North America"
  },
  {
    "year": 1929,
    "name": "Stock Market Crash",
    "place": "North America"
  },
  {
    "year": 1933,
    "name": "FDR’s First Fireside Chat",
    "place": "North America"
  },
  {
    "year": 1945,
    "name": "The Atomic Bombing of Hiroshima and Nagasaki",
    "place": "North America"
  },
  {
    "year": 1954,
    "name": "U.S. Army–McCarthy Hearings",
    "place": "North America"
  },
  {
    "year": 1968,
    "name": "Assassination of Martin Luther King, Jr.",
    "place": "North America"
  },
  {
    "year": 1972,
    "name": "Watergate Scandal",
    "place": "North America"
  },
  {
    "year": 1981,
    "name": "PATCO Strike",
    "place": "North America"
  },
  {
    "year": 1998,
    "name": "The Monica Lewinsky Affair",
    "place": "North America"
  },
  {
    "year": null,
    "name": "September 11 Attacks",
    "place": "North America"
  },
  {
    "year": 2016,
    "name": "Election of Donald Trump",
    "place": "North America"
  }
];