KNOW IT ALL: Wednesday’s Top 8 Stories at NBC News

Good morning. Here are some of the headlines we're following this morning:

1. Sanders Scores Major Upset as Trump Tallies Important Wins

Entering Tuesday’s primaries, there was talk that Bernie Sanders’ campaign was all but dead. Never mind all that. Sanders had one of his most important victories of the Democratic race, winning his first primary in a state with a large (23 percent) black electorate and carrying a state where Hillary Clinton was the favorite. Read more in POLITICS.

2. Trump Rolls Over Rubio as Decisive Contests Near

Donald Trump shrugged off continuous attacks from his rivals, damaging stories in the press, and regular confusion over his own policy platform to end the week where he began: the front-runner for the Republican nomination. At the same time, Senator Marco Rubio, the candidate many in the establishment pegged as their champion, appears to be on life support. Read more in POLITICS.

Trump Predicts Wins in Ohio and Beyond 21:41

3. Quadruple Homicide Suspect Found Hiding in Ditch

A fugitive gunman wanted in the shooting deaths of five men — including a quadruple homicide inside a Kansas City home — was arrested early Wednesday in a ditch next to a Missouri highway. Read more in NEWS.

4. Suspect in Pastor's Shooting Arrested Outside White House

Kyle Andrew Odom, the ex-Marine accused of shooting a prominent Idaho minister outside his church, was arrested by the U.S. Secret Service in Washington, D.C., after he threw objects over the White House fence, police said. The Secret Service confirmed the arrest to NBC News late Tuesday night. Read more in NEWS.

5. Judge Upholds Same-Sex Marriage Ban in Puerto Rico

A federal judge on Tuesday upheld Puerto Rico's same-sex marriage ban, ruling that last year's landmark Supreme Court decision on marriage rights doesn't necessarily apply to the unincorporated territory. Read more in NEWS.

6. O Canada! What to Know About 'Dreamy' PM's U.S. Visit

Sure, the first official visit to the U.S. by a Canadian prime minister in 19 years is an opportunity for the countries to deepen their close relationship. But Justin Trudeau's sex appeal is also attracting attention — and headlines — ahead of Thursday's trip to the White House. Bloomberg cited his "boyish charm and pedigree" and Politico quoted a senior Obama administration official who called Trudeau “dreamy.” Read more in NEWS.

7. 'Fifth Beatle' George Martin Dead at 90

George Martin, the Beatles producer and arranger who supervised most of the band's era-defining recordings — from "Love Me Do" through the psychedelia of "Sgt. Pepper's Lonely Hearts Club Band" to their final collaborations on "Abbey Road" — has died at the age of 90. Read more in POP CULTURE.

George Martin Reflects On a Lifetime in Music 0:48

8. Machine Plays 'Perfectly,' Defeats Board Game Champion

The world champion of an ancient but fiendishly complicated board game was defeated by the latest in computer technology in the first match of a series aiming to help determine whether a machine can imitate human intuition. Read more in TECH.