The name on the building's gold-plated sign said Trump.
The water pouring off the red marble wall inside said - in its own way - Trump. And the coiffured hair could not have belonged to anyone else.
The "takeaway news" from Mr Trump's Thursday press conference in New York was that he had bowed to pressure and pledged to sign the Republicans' so-called pledge of loyalty. That means, whoever eventually emerges successful from the crowded field Mr Trump currently leads by a country mile, he will in theory be obliged to support them.
Mr Trump spoke to reporters in New York
But if that was the news line, the optics of the press conference were very different. It was noticeable that Republican Chairman Reince Priebus had come to Mr Trump's office to finalise the agreement, not the other way around, and the tycoon appeared to leave himself some wiggle room should things not go his way.
"I see no circumstances under which I would tear up that pledge," Mr Trump said at Trump Tower, without needing to point out that circumstances can always change. No one asked if the document was legally binding.
US media said his pledge of loyalty on Thursday was a victory for Republican National Committee in its efforts to rein in the billionaire, who leads opinion polls but has upset mainstream Republicans with his brash style and barbed and personal attacks on rivals.
There is concern within the party that an independent run by Mr Trump could split support for the party and give the Democrats a huge boost.
Here's how Trump will get out of his loyalty pledge http://t.co/cYKh37jl4d pic.twitter.com/6wpjrkJ44l
— Jonathan Chait (@jonathanchait) September 3, 2015
"The best way forward ... to win, is if I win the nomination and go direct against whoever (the Democrats) happen to put up. So for that reason, I have signed the pledge," Mr Trump said.
"So, I will be totally pledging my allegiance to the Republican Party and the conservative principles for which it stands, and we will go out and we will fight hard and we will win."
Mr Trump's 25 minute performance was full of Trumpisms and swagger. And he was ready when he was asked about a possible challenge from Kanye West, who earlier this week suggested he might run for the White House in 2020.
"Kanye West has been so great," said Mr Trump. "He goes around saying 'Trump is my all-time hero'. He says it to everybody. So, Kanye West, I love him."
