Image: Watergate Complex, Washinton, D.C. Indutiomarus [Public domain], via Wikimedia Commons
The word Watergate or it's derivatives (pick your word-gate) are synonymous with secret, illegal activities.
In 1972, the Democratic National Committee had an office in the Watergate complex in Washington, D.C. A break-in occurred, five men were arrested, and cash found on the burglars was linked to a slush fund used to re-elect President Nixon.
Image: Tonynetone, famous image of Nixon leaving the White House, often paired with his now infamous quote, "I am not a crook."
It turned out that Nixon and his aides had abused their power, using the FBI, CIA, and IRS to investigate activist groups and their political opponents. Tapes of damaging conversations in the oval office "revealed that Nixon had attempted to cover up activities that took place after the break-in, and (he used) federal officials to deflect the investigation." Nixon resigned before he could be impeached, but received a pardon from his replacement, Gerald Ford. (Source)
Image: Anti-Ford button made for 1976 presidential election, Wikipedia Commons
One of the goals of the Watergate break-in was to install listening devices into the phones. More recently, President Trump accused former President Obama of wiretapping Trump Towers during the 2016 election although no evidence has been found to support his claims. Newsweek posted an article about surveillance on Trump Tower from 2011 to 2013, but this was aimed at a Russian crime ring involved in money laundering, sports gambling and extortion, not Trump.
Have you seen the movie All The President's Men or studied the Watergate Scandal?