Photo Gallery: How the crisis at the southern border unfolded, and spiraled out of control

Shortly after President Biden took office in January 2021, migrant encounters at the southern border – which had been rising for months – shot up dramatically. They have remained at historic highs for months and show no immediate sign of slowing down. The crisis has at time consumed the administration, but it has remained resolute in its approach to the matter.  ((Idalia Rie / Eyepix Group/Future Publishing via Getty Images))

As numbers, particularly of unaccompanied children, started rising, the Biden administration quickly found itself overwhelmed. A controversy quickly circulated around the conditions in a holding facility in Donna, Texas – where more than 4,100 migrants, mostly unaccompanied minors, were packed into the facility that had a capacity of just 250 during the early days of the COVID-19 pandemic. ( )

Journalists and Republicans criticized the administration for not allowing access to the facility.(AP Photo/Dario Lopez-Mills, Pool) (AP)

Meanwhile, border numbers were rocketing. Numbers jumped from 78,000 in January to more than 173,000 in March – and would reach more than 200,000 by July.  (CBP)

As the numbers shot up, Republicans blamed the Biden administration's ending of Trump-era border policies. The Biden administration, instead, blamed "root causes" like poverty, violence and climate change in Central America. Vice President Kamala Harris was assigned to the job of leading talks in Central America -- and was quickly dubbed "border czar."  ( (Photo by Drew Angerer/Getty Images))

Harris visited Guatemala and Mexico, where she told migrants "do not come" and unveiled a number of measures and investments designed to combat the "root causes." ((AP Photo/Jacquelyn Martin))

She was criticized for not having visited the U.S. border, including when she quipped that she also had not been to Europe. ( (Photo by JIM WATSON/AFP via Getty Images))

A visit to the U.S. border soon followed, although critics noted she went to the relatively quiet area of El Paso, Texas, rather than Yuma, Arizona or the Rio Grande Valley. ( (Photo by PATRICK T. FALLON/AFP via Getty Images))

In Congress, efforts to grant amnesty to illegal immigrants was underway. A broad immigration reform bill, with amnesty for millions but with no border security measures, failed due to a lack of Republican support. Lawmakers pushed to include some form of amnesty in a budget reconciliation bill -- an effort that would be ultimately killed off by Sen. Joe Manchin, D-W.Va. (AP Photo/J. Scott Applewhite)

As numbers hit a high for the year in August, the Biden administration suffered another legal defeat. A federal judge ordered the administration to re-implement the Trump-era "Remain-in-Mexico" policy, which had been used to keep migrants in Mexico for their immigration hearings. The judge found that the termination of the policy had contributed to the border surge -- and the order was later upheld by the Supreme Court. ((Ricardo Santos/The Laredo Morning Times via AP))

Meanwhile, governors in southern states pushed back. As their attorneys general were filing legal challenges, some states took matters into their own hands. Governors Abbott of Texas and Ducey of Arizona called for help from other states. States like Florida, South Dakota and Iowa responded.  (Fox News )

Meanwhile, Texas began building its own border wall -- a Trump-era project that the Biden administration had ended abruptly. It also launched Operation Lone Star, which surged law enforcement and resources to stop illegal immigrants at the border. (AP Photo/Eric Gay, File) ( (AP Photo/Eric Gay, File))

The Biden administration faced a new crisis in September, when thousands of predominantly Haitian migrants surged into Del Rio, and ended up camped under the International Bridge in squalid conditions. DHS surged Border Patrol agents and resources, leaving other areas of the border exposed.  (AP Photo/Julio Cortez)

Eventually, while a number were deported, many of the Haitians were allowed into the United States to claim asylum, despite DHS Secretary Alejandro Mayorkas’ claim that migrants’ efforts "will not succeed." (PAUL RATJE/AFP via Getty Images)

The Haitian migrant crisis led to a scandal for the Biden administration after false reports that Border Patrol agents on horseback had whipped migrants were echoed by top Democrats and members of the administration – including President Biden. ((Photo by PAUL RATJE/AFP via Getty Images))

In fact, the agents had used their reins to control the horses in the Del Rio River, but that had been misinterpreted as them using whips. But Mayorkas and Harris condemned the scenes, and an investigation was launched -- an investigation that has still not formally concluded. ( )

Numbers slowed during last months of 2021 but by December there were still 179,254 encounters, up from 73,994 in December 2020. By March, that number shot up to 222,144.  ( (Photo by Brandon Bell/Getty Images))

In April, the Biden administration announced that it would be ending Title 42 expulsions, which had been in place since March 2020. (Fox News)

The order had been used to expel a majority of migrants due to the COVID-19 pandemic. The administration said it would end the order on May 23.  (Nicolo Filippo Rosso/Bloomberg via Getty Images)

That move sparked outrage from moderate Democrats as well as Republicans, fearing an even bigger surge at the border. A number of Democrats – including both Democratic senators in Arizona -- signed onto legislation to stop the move.  (Sen. Mark Kelly office )

Ultimately, a Louisiana district court imposed a preliminary injunction on the move, siding with a Republican lawsuit from 24 states which said it would increase costs to the state and was unlawful. (AP Photo/Marco Ugarte, File)

As that court fight was ongoing, Customs and Border Protection announced that there had been 234,000 migrant encounters in April alone.  (AP Photo/Eric Gay, File)

DHS Secretary Alejandro Mayorkas said he expects numbers to rise in the coming weeks, but that it has a plan to deal with the surge – but pleaded with migrants: 'Do not come to the border'.  (Pool video)