Imitation road signs on the Creggan Estate in Derry, Londonderry tell locals in no uncertain terms that they should not cooperate with police in the aftermath of Lyra McKee's murder. This image of a rat with a gun's crosshairs trained on it is captioned "Informers will be shot," and signed "IRA," in reference to the Irish Republican Army terror group.

Cleanup efforts have already taken place in the area: The white walls of the building opposite have a fresh coat of paint to cover extreme nationalist graffiti. But as quickly as the threats are cleared, new ones appear. Local police have said that it's not their responsibility to clear away such material, possibly suspecting that their presence for this task could do more harm than good.

In the immediate aftermath of the April riots on Creggan Estate, when Lyra McKee was shot while observing the unrest near a police 4x4 vehicle, messages of solidarity were posted and pro-IRA graffiti was altered to send messages of peace instead. But eventually, ordinary people's defiance wanes. This sign warns against talking to the RUC (Royal Ulster Constabulary, Northern Ireland's police).

On the same street, just across the road from the mock road signs, the local car wash carries a large poster calling for the release of nationalist or republican prisoners arrested by Northern Irish authorities. Many houses are decorated in similar ways in the area. Irish flags are another common sight.

A short walk away, the picturesque Creggan Parish Church graveyard peers down on the estuary and the city below. Most of the graves belong to ordinary people, but paramilitary monuments to former members of the Irish National Liberation Army (INLA) — an Irish republican paramilitary group formed during Ireland's "Troubles" — also take pride of place at the burial site.

Creggan Estate is just up the hill from the 1972 "Bloody Sunday" (or "Bogside Massacre") memorial, near Derry's "Peace Wall" separating the nationalist, largely Catholic population from the loyalist, majority Protestant part of the city. British soldiers shot 28 unarmed civilians at what began as a protest. Thirteen died outright, another later of his wounds. Seven were 21 or younger.

The memorial is regularly tended to and visited. Catholic crucifixes are a common sight, with the Irish nationalist cause intertwined with Catholicism.

Derry's name was officially given the prefix "London" in 1613. Its city council failed in a 2007 court bid to rename it Derry on the maps. Now with a majority republican, Catholic population, Northern Ireland's second-largest city has immense historical significance to both sides. The Battle of Bogside, a 1969 communal riot, is broadly seen as the start of the "Troubles" of the late 20th century.

Free Derry Corner marks the entry to the nationalist, predominantly Catholic part of the city, including Creggan. The entire area is awash with murals, memorials and sometimes less tasteful messages. Derry, Londonderry is now majority nationalist and Catholic. But the 1689 Siege of Derry was also a key event in the revolution that overthrew the last Catholic king of England, James II.

In the immediate aftermath of McKee's murder, the entry was repainted in her honor. It has since been restored to usual.

Another photo taken in April, soon after McKee's death, when locals were unwilling to let terrorist messages stand. A local primary school is nearby.

This vacant building on Bogside near the Peace Wall was the proposed site of an unsanctioned protest. Local kids had piled tires high at this site, planning what they were calling the 2019 Bogside Bonfire. After public pressure, and failed attempts by the nationalist Sinn Fein political party to dissuade the children, authorities cleared out the inflammable material on August 1.

Barbed wire and sharp anti-climbing spikes on gates are not unusual forms of home security in parts of the city. Businesses tend to be especially well-fortified.

Visitors can tour the Free Derry area of the city. Local guides take people on foot, while taxi drivers also offer personal tours. There's also a Museum of Free Derry. Many of the walls are adorned with murals, such as this one picturing a home raid by the military.

One new placard near Free Derry Corner has a distinct Brexit flavor. "Hard Border, Soft Border, No Border, #IrishUnityNow," it reads. In the background, on the back of a road sign, you can also make out the graffiti "RIRA," short for "Real Irish Republican Army," one of the splinter groups (also known as the New IRA) that rejected the IRA's cease-fire in 1997 ahead of the Good Friday Agreement.

On the other side of town, near the train station, a bright blue poster carries a quote from Lyra McKee. McKee's book, Angels with Blue Faces, was published posthumously this past week. It's the upshot of a five-year investigation by McKee into the IRA's 1981 murders of Ulster Unionist (or British loyalist) MP Robert Bradford and another man, Kenneth Campbell.

Despite the continued troubles in places like Creggan, or the permanent red-white-and-blue (UK flag colors) bunting on show in loyalist parts of town like Bonds Street, much of Derry, Londonderry has been transformed in recent years. One unmissable feature of this, straddling the estuary on which the city was built, is the Peace Bridge. The plaque also notes that it was funded by the EU.

Derry's Peace Flame, near the waterfront and the Peace Bridge, was lit by children from both communities in 2013, ahead of a speech by Martin Luther King Jr. Like much of the city center, it symbolizes the progress made — even in Derry, Londonderry — over the past two decades in Northern Ireland. That said, vandals did target it 2016, while in 2017, a technical fault put out the fire.